The Bugatti Project
Building a Stevenson Pedal Bugatti -Type 35
Preamble
1. The Kingpins
2. The Wheels
3. The Chassis
4. The Steering Components
5. The Drive Train
6. The Body
7. Installing the Steering Column
8. Fitting the Rear Wheels
9. The Pedal System
10. Hood and Bonnet
11.The Steering Wheel
12. Gadgetry
13. The Windscreen
14. The Finish
1. The Kingpins
2. The Wheels
3. The Chassis
4. The Steering Components
5. The Drive Train
6. The Body
7. Installing the Steering Column
8. Fitting the Rear Wheels
9. The Pedal System
10. Hood and Bonnet
11.The Steering Wheel
12. Gadgetry
13. The Windscreen
14. The Finish
There are times in the
boatbuilder's day when nothing more can be done on the boat, because of
drying glue, or paint, or some other inevitable delay. This is not
wasted time: it allows room for a second project!
Having become a grandfather in
2006, my thoughts have been turned to toys, specifically pedal cars.
The
plastic stuff I was "encouraged" to buy for a few hundred dollars might
be all very
well for their intended users, but they lack a certain élan. How
much better would it be to make one!
There are a number of plans available for these cars, but the one I chose was the Stevenson plan for a pedal Bugatti Type 35. The Stevensons also published a book some years ago on a build-it-yourself downhill racer for 10 year olds, which revelled under the Wodehousian name of the "Buffy-Porson". They now concentrate mainly on backyard boat projects, but their Bugatti is a serious attempt to capture the romance of the era, and cannot be bettered for the amateur. Their website is http://www.stevproj.com/PedBBB.html .
What really appeals to me about this car, and all the Stevenson projects, is that they are based on the sealing wax and string philosophy: keep it simple. (In the case of the Buffy-Porson that concept is almost literally what constitutes the braking system, which may account for why it is out of print).
The original Bugatti pedal car (left) as designed by the Stevensons,
and a swank modified version (right).
There are a number of plans available for these cars, but the one I chose was the Stevenson plan for a pedal Bugatti Type 35. The Stevensons also published a book some years ago on a build-it-yourself downhill racer for 10 year olds, which revelled under the Wodehousian name of the "Buffy-Porson". They now concentrate mainly on backyard boat projects, but their Bugatti is a serious attempt to capture the romance of the era, and cannot be bettered for the amateur. Their website is http://www.stevproj.com/PedBBB.html .
What really appeals to me about this car, and all the Stevenson projects, is that they are based on the sealing wax and string philosophy: keep it simple. (In the case of the Buffy-Porson that concept is almost literally what constitutes the braking system, which may account for why it is out of print).
The original Bugatti pedal car (left) as designed by the Stevensons,
and a swank modified version (right).
In deciding to embark on any
plan project from overseas, in this case the USA, one has to be aware
of
the limitations of available materials, especially here is Australia
where choice is restricted and prices are high. There is also often a
problem with metric versus Imperial measurements. This project
certainly proves the point.
What follows is a description of some of the material problems I encountered, and my ways of overcoming them. It includes some complaints about inconsistencies in the plans, and explains why I ended up with such a narrow cabin in my Bugatti!
1.The first hurdle is the 'tire' which is specified for the rather elaborate wheels. The Schwinn bicycle company used to make 16 inch x 2.125 tyres to fit their S2 wheels, but not any longer. They had a tread on them which looked more like a car tyre than a bicycle, but the emergence of BMX bikes has just about killed off the competition, so that now all you can get is the knobby type which looks quite out of place on the bitumen. Some old unused stock can occasionally be found on places like Ebay, but at high prices, and their condition cannot be guaranteed. The design of the wheels means that the tyres run on the rims anyway, so their life expectancy must be limited. Even if you find the specified Schwinn brand you will have to replace them sometime. Some electric wheelchairs have tyres of this size, but they hardly look appropriate either. You are probably best advised to get the least offensive bike tyre you can find, and put up with it. The kid won't mind in the slightest.
I eventually settled on tyres for electric bicycles from Australian All Electric Vehicles, http://www.aaev.com.au They are not the square profile of the original Schwinn tyres, but they are not the full knobby array either. It is difficult enough to get 16 x 2.125 tyres anyway, so I am just glad to get some which will fit.
2.Next, remember that when an American site calls for 1" x 6" timber, it means before dressing. They actually expect you to get some 3/4" thick stock. The plans call for fir (presumably Douglas) or spruce - good luck. But radiata pine will also work for most of the parts, with some light hardwood called for in the stress bearing components.
3.The biggest problem is in the plumbing supplies which are used to manufacture the drive train and steering components. For starters, they are of galvanised iron, which is rapidly being replaced by more modern materials. Secondly, they are in a range of sizes which just do not exist here any more.
For example, the king pins are made up of 1/2" T pieces, joined to two 1" and one 3" nipple. Our nipples have hex sections in the middle so that their threads are not damaged by tightening, but the ones referred to in the plans are like small pipes, threaded at both ends. The lengths specified are not available here as nipples. Instead, substitute either short pipes or all threads, but in the latter case you will probably have to use brass instead of gal.
Attached to the short nipples are 1/2" female to 3/4" male bushings. We have those, but they need to be 1" long. Ours are only 3/4" long. Since they have to emerge through a piece of 3/4" timber the shorter ones will not do. There might still be a few of the older long ones to be found in places like to ancient hardware store, but the dominance of Bunnings has ensured that your choice is very limited when it comes to hardware. Even plumbing supplies stores cannot come up with them on demand, although some of the bigger ones may be able to get them in, provided the order is big enough, which, in this case, it clearly will not be.
The bushings are tightened into position by "electrical conduit lock nuts", which are unknown except in plastic now. Galvanised back nuts can be used instead, but they may have to be artificially locked down, as they have no real resistance to unwinding over time.
When it comes to the drive train, the specified 3/8" pipes and fittings might prove to be impossible to acquire. The plans does mention that 1/2" can be substituted if necessary, but that 3/8" is preferable to save weight. You might have to go with the 1/2" and console yourself that at least the kid won't get obese pushing all that extra weight around.
Now, as a woodworker, but not a metalworker, I was lulled into a sense of foolhardy security by the reassurance that the task was within the ability of even the complete novice with a hand drill. Having almost removed my thumb on the first metalworking task, I decided that it was time to educate myself about the basics of metalworking. (The treacherous job which was almost my undoing was drilling a 1/2" hole in the T pieces.) It was only after that that I discovered that the 1/2" x 7" bolts for which the holes were intended are not readily available here either. If you want 7" (actually 180 mm.) you will only get it in M12, unless you get a cup head bolt. Nevertheless, it pays to bone up on metal drilling, and a metal vise for the drill press is probably a very good investment.
One of the really annoying instructions is to drill out the wheel hubs to 1/2" to accept a copper tube bearing of 1/2" internal diameter!!! for the 1/2" bolt axles. A drill of the exact diameter of the tubing is then used to expand the hole to accept the bearing. What must be meant is that the hole is reamed to the outside diameter of the tube. But the problem here is that our tubing is sold as O.D. not I.D., so 1/2" tubing will not accept a 1/2" bolt anyway, even bearing in mind that the measurement of a bolt refers to its thread diameter, and not its shank, which is a bit narrower. (Perversely, the half inch copper tubing in question is sometimes labelled 15 mm. here instead of 12.7 mm.). So, you will have to find some combination of axle bolts, copper tubing and reamers which will result in a good fit.
These frustrations are not peculiar to the Bugatti project. It seems that all overseas plans have some limitations on them because of our paucity of materials in Australia, and whereas our friends across the oceans can gather up their materials in a single trip to their local supplier, we have constantly to be on the lookout for the components throughout the project, which makes it difficult to plan ahead. But that is no reason to delay, so....
1. The Kingpins
Anyway, after a few days of scrounging around hardware shops and plumbing suppliers, I was able to come up with the parts for this kingpin. The axle bolt still has its head attached, which will need to be removed for the wheel to go on, and the back of the pipe which substitutes for the 3" nipple still has its thread on it. This can be removed later, or left on if it does not interfere.
The brass, which is showing through, substitutes for the 1" nipple, and the lock nuts on the bushings are standard plumbing back nuts. They might need a bit of Loctite on them to stop them working loose. But basically what we have is a unit which will fit into the space allowed between the cross members of the steering, and which should do the job.
The kingpin shown here uses brass all thread instead of the 1" nipple, and a 4" pipe instead of a 3" nipple.
2. The Wheels
All this concentration on the king pins comes out of sequence for the construction of the car as laid down in the plans, because I was keen to ensure that I could actually acquire the necessary material. But the first task specified is to make the wheels.
Some considerable care has been taken to ensure that the wheels look like the original Bugatti wheels, and spoked bicycle wheels are not catered for. The actual wheel discs are cut from 12" wide stock, but since they are over 15" in diameter they have to be made up in two sections joined together. These days it is easy enough to get hold of some laminated pine in widths of 405 mm., so they can be cut out of a single piece. Whereas the plans call for freehand sabre sawing of the outlines, you will probably save yourself a good deal of anxiety if you go to the trouble of building yourself a trammel for the saw, so that the circumferences are truly circular. A number of different diameter discs have to be cut for these wheels, so make sure that the trammel is adjustable for radius.
I constructed a simple trammel from a piece of 6 mm. ply wood with a small diameter lag screw in one end and some double sided tape on the other. The jig saw was mounted on top of the ply with the tape on its sole, such that the distance between the screw and the close edge of the saw blade was the desired radius. Adjustments can be made by moving either the screw or the tape and saw. The saw is then placed tangentially against the stock, and the screw is driven into it at the point which will be its centre. This can be repeated three more times after the first cut, using the uncut edges of the stock for the tangential placement each time.
The trammel for the circular cuts showing four holes for the screw (or hook) and the double sided tape. The blade travels
in the kerf between the pieces of tape.
3. The Chassis
The chassis consists of two side frame rails, joined to a rear cross member placed vertically, and two front cross members placed horizontally which house between them the kingpins for the steering system. It is simple in the extreme, relying on screw and glue technology for its strength. The largest components, the frame rails, are made from 1 x 6 pieces of fir or pine which are cut to shape from the lofting provided by the plan. The second could be shaped from the first with a router and copying bit.
The original Bugatti T35 had extensive louvres, not only on the hood, but also on the frame where they served no purpose other than decoration. As a nod to the latter, but not to get involved in all the work which would be required in reproducing them, the Stevensons provide a pattern of "lightening holes" 1/4" deep in the rails as a substitute. These are seen above.
After squaring the structure, the glue is applied to the rear cross member and a stiff chassis results.
The chassis after refitting of the front cross members and kingpins.
4. The Steering Components
The cross members are now removed from the chassis, and drilled to accept the kingpins as described in the plans. Even although I used hardwood for these pieces, there was a tendency for them to split as the kingpins were tightened home into them. That is partly because the bushings were rather poorly cast, and sloped outwards at their shoulders, but partly too because of the proximity of the holes to the end of the boards. Only 1/2" of meat to resist a lot of force. I think an extra 1/2" would have helped here; but I was stuck with what I had cut, so I filed down the shoulders of the bushings as best I could, and I will reinforce the areas with epoxy and fibreglass later.
Holes cut for the kingpins.
A trial fitting with the bushing (left),
and a hex nipple
helps to drive it in (right).
The bushing is flush with the surface of the cross member, and protrudes enough on the other side for the lock nut.
Lock nut applied (left), and the kingpin assembly screwed on (right).
The steering mechanism assembled.
What follows is a description of some of the material problems I encountered, and my ways of overcoming them. It includes some complaints about inconsistencies in the plans, and explains why I ended up with such a narrow cabin in my Bugatti!
1.The first hurdle is the 'tire' which is specified for the rather elaborate wheels. The Schwinn bicycle company used to make 16 inch x 2.125 tyres to fit their S2 wheels, but not any longer. They had a tread on them which looked more like a car tyre than a bicycle, but the emergence of BMX bikes has just about killed off the competition, so that now all you can get is the knobby type which looks quite out of place on the bitumen. Some old unused stock can occasionally be found on places like Ebay, but at high prices, and their condition cannot be guaranteed. The design of the wheels means that the tyres run on the rims anyway, so their life expectancy must be limited. Even if you find the specified Schwinn brand you will have to replace them sometime. Some electric wheelchairs have tyres of this size, but they hardly look appropriate either. You are probably best advised to get the least offensive bike tyre you can find, and put up with it. The kid won't mind in the slightest.
I eventually settled on tyres for electric bicycles from Australian All Electric Vehicles, http://www.aaev.com.au They are not the square profile of the original Schwinn tyres, but they are not the full knobby array either. It is difficult enough to get 16 x 2.125 tyres anyway, so I am just glad to get some which will fit.
2.Next, remember that when an American site calls for 1" x 6" timber, it means before dressing. They actually expect you to get some 3/4" thick stock. The plans call for fir (presumably Douglas) or spruce - good luck. But radiata pine will also work for most of the parts, with some light hardwood called for in the stress bearing components.
3.The biggest problem is in the plumbing supplies which are used to manufacture the drive train and steering components. For starters, they are of galvanised iron, which is rapidly being replaced by more modern materials. Secondly, they are in a range of sizes which just do not exist here any more.
For example, the king pins are made up of 1/2" T pieces, joined to two 1" and one 3" nipple. Our nipples have hex sections in the middle so that their threads are not damaged by tightening, but the ones referred to in the plans are like small pipes, threaded at both ends. The lengths specified are not available here as nipples. Instead, substitute either short pipes or all threads, but in the latter case you will probably have to use brass instead of gal.
Attached to the short nipples are 1/2" female to 3/4" male bushings. We have those, but they need to be 1" long. Ours are only 3/4" long. Since they have to emerge through a piece of 3/4" timber the shorter ones will not do. There might still be a few of the older long ones to be found in places like to ancient hardware store, but the dominance of Bunnings has ensured that your choice is very limited when it comes to hardware. Even plumbing supplies stores cannot come up with them on demand, although some of the bigger ones may be able to get them in, provided the order is big enough, which, in this case, it clearly will not be.
The bushings are tightened into position by "electrical conduit lock nuts", which are unknown except in plastic now. Galvanised back nuts can be used instead, but they may have to be artificially locked down, as they have no real resistance to unwinding over time.
When it comes to the drive train, the specified 3/8" pipes and fittings might prove to be impossible to acquire. The plans does mention that 1/2" can be substituted if necessary, but that 3/8" is preferable to save weight. You might have to go with the 1/2" and console yourself that at least the kid won't get obese pushing all that extra weight around.
Now, as a woodworker, but not a metalworker, I was lulled into a sense of foolhardy security by the reassurance that the task was within the ability of even the complete novice with a hand drill. Having almost removed my thumb on the first metalworking task, I decided that it was time to educate myself about the basics of metalworking. (The treacherous job which was almost my undoing was drilling a 1/2" hole in the T pieces.) It was only after that that I discovered that the 1/2" x 7" bolts for which the holes were intended are not readily available here either. If you want 7" (actually 180 mm.) you will only get it in M12, unless you get a cup head bolt. Nevertheless, it pays to bone up on metal drilling, and a metal vise for the drill press is probably a very good investment.
One of the really annoying instructions is to drill out the wheel hubs to 1/2" to accept a copper tube bearing of 1/2" internal diameter!!! for the 1/2" bolt axles. A drill of the exact diameter of the tubing is then used to expand the hole to accept the bearing. What must be meant is that the hole is reamed to the outside diameter of the tube. But the problem here is that our tubing is sold as O.D. not I.D., so 1/2" tubing will not accept a 1/2" bolt anyway, even bearing in mind that the measurement of a bolt refers to its thread diameter, and not its shank, which is a bit narrower. (Perversely, the half inch copper tubing in question is sometimes labelled 15 mm. here instead of 12.7 mm.). So, you will have to find some combination of axle bolts, copper tubing and reamers which will result in a good fit.
These frustrations are not peculiar to the Bugatti project. It seems that all overseas plans have some limitations on them because of our paucity of materials in Australia, and whereas our friends across the oceans can gather up their materials in a single trip to their local supplier, we have constantly to be on the lookout for the components throughout the project, which makes it difficult to plan ahead. But that is no reason to delay, so....
1. The Kingpins
Anyway, after a few days of scrounging around hardware shops and plumbing suppliers, I was able to come up with the parts for this kingpin. The axle bolt still has its head attached, which will need to be removed for the wheel to go on, and the back of the pipe which substitutes for the 3" nipple still has its thread on it. This can be removed later, or left on if it does not interfere.
The brass, which is showing through, substitutes for the 1" nipple, and the lock nuts on the bushings are standard plumbing back nuts. They might need a bit of Loctite on them to stop them working loose. But basically what we have is a unit which will fit into the space allowed between the cross members of the steering, and which should do the job.
The kingpin shown here uses brass all thread instead of the 1" nipple, and a 4" pipe instead of a 3" nipple.
2. The Wheels
All this concentration on the king pins comes out of sequence for the construction of the car as laid down in the plans, because I was keen to ensure that I could actually acquire the necessary material. But the first task specified is to make the wheels.
Some considerable care has been taken to ensure that the wheels look like the original Bugatti wheels, and spoked bicycle wheels are not catered for. The actual wheel discs are cut from 12" wide stock, but since they are over 15" in diameter they have to be made up in two sections joined together. These days it is easy enough to get hold of some laminated pine in widths of 405 mm., so they can be cut out of a single piece. Whereas the plans call for freehand sabre sawing of the outlines, you will probably save yourself a good deal of anxiety if you go to the trouble of building yourself a trammel for the saw, so that the circumferences are truly circular. A number of different diameter discs have to be cut for these wheels, so make sure that the trammel is adjustable for radius.
I constructed a simple trammel from a piece of 6 mm. ply wood with a small diameter lag screw in one end and some double sided tape on the other. The jig saw was mounted on top of the ply with the tape on its sole, such that the distance between the screw and the close edge of the saw blade was the desired radius. Adjustments can be made by moving either the screw or the tape and saw. The saw is then placed tangentially against the stock, and the screw is driven into it at the point which will be its centre. This can be repeated three more times after the first cut, using the uncut edges of the stock for the tangential placement each time.
The trammel for the circular cuts showing four holes for the screw (or hook) and the double sided tape. The blade travels
in the kerf between the pieces of tape.
The age old problem with sabre
saws is deviation of the blade, and cutting a circle seems to be the
worst possible thing to do for deviation. My saw deviates away from the
work piece, but if it deviates towards a larger radius will have to be
used so as not to undercut the finished diameter.
To square up the edges after the initial cut out is performed I set up a carousel arrangement on the table saw, whose blade is thick enough not to wander.
To square up the edges after the initial cut out is performed I set up a carousel arrangement on the table saw, whose blade is thick enough not to wander.
Of course, this cannot be used
on inside diameters, such as are encountered on the reinforcing ply
rings which are attached to the wheel discs. Here, the sabre saw can be
used, as the smaller thickness of the ply is less likely to deflect the
blade.
The wheel design is such that the total thickness of wood inside the tyre is only 1-1/8", which does not seem much to go inside a 2.125" tyre, but after cutting all these discs I'm not arguing!
What I might argue, however, is the suitability of these wheels in the first place. While they look all very well, I have noticed that the discs have started to warp as soon as they were cut. Perhaps some bicycle wheels would be more practical. If the authentic look is important, laminated wheels made up of three 1/4" ply discs would be more stable. However, I am committed now, so, on to the rims discs...
These can be cut in their circumference while attached to the wheels, so as to ensure that they fit the wheels perfectly. Their attachment to an underlying solid surface also helps prevent splintering of the ply where the blade crosses the grain. In a short time, a full set of wheels and rims are ready.
The inner circumference of these rims is a more
difficult proposition. To avoid splintering here, I score the
cutting line on both sides with a scribe, and deepen the score until it
makes
a significant cut through the fibres of the outer plies. Then, I cut
almost but not quite to the line with a sabre saw, and finish the job
with a curved sole spokeshave, carefully creeping up to the scored
line.
As long as the inner circumference of the ring is rounded beforehand, the rest can be done on the router table after the ring is glued to the wheel. Just remember to keep the brads which hold the two together out of the path of the router bit. Brads are used at approximately 3" centres to hold the ring onto the wheel, and yellow glue is alright, since this joint will be protected from water by its location inside the tyre.
The purpose of these rims is to reinforce the wheels and to thicken them where they meet the inside of the tyres. The cut out waste is used to manufacture the "brake discs" which attach to the inside of the wheels. These latter members act in concert with the spoke discs on the outside to hold the tyres onto the wheels. There is a discrepancy in the plans regarding the dimension of the brake discs. They are shown to have dimensions of 12-1/2", whereas the instruction says to cut them to 12-1/4". The correct dimension is 12-1/2". The rim discs are 13" inside diameter, so there is only a 1/4" gap between the outside of the brake disc and the inside of the rim, (the two 1/4" making up the 1/2" difference in diameter).
The composite structure now looks like this:
A wheel with its reinforcing disc applied and rounded over.
When it comes time to cut the spoke discs, no actual diameter is given. Instead, a template on the plans is available. (Actually, two templates are given). However, the diameter of both of them is 12-1/4", which can't be right, because they have to be the same as the brake discs. The instruction with one of the templates states: "After drawing outside of pattern and cutting outside of line, dia. should be close the 12-1/2"." Why not make the pattern accurate and cut and draw right on the lines?
Now, the spoke disc is held out from the centre of the wheel by a 3/4" thick hub, and its outer edge is held against the tyre by a ring which is screwed through the spokes and the wheel, clamping the tyre between spoke disc and wheel. The outside diameter of the ring is 12-1/2", so the diameter of the spoke disc should be the same when in position. But because of the hub holding out its centre, this means that it should be cut greater than 12-1/2", not less. If you work it out it should really be cut to a diameter of 12-3/4". Nevertheless, if you have already cut the spoke disc to 12-1/2", as I have, there will only be a discrepancy of less than 1/8" all round, which will be obscured by the tyre anyway, so it does not really matter.
But it is a warning about the dimensions on the plans, especially on the templates. They all need to be double checked before cutting.
The hubs which attach to the outside of the wheels and hold out the spoke discs are to be 3-1/8" in diameter, so that they can accept the fixation of the 3" flanges which support the wheel axles. I have only been able to acquire 4" flanges, so I have to increase the diameter of the hubs accordingly, and also the diameter of the central part of the spoke discs. The spokes on my car will have to be 1/2" shorter than on the Stevensons' car.
The spoke disc is marked up and fitted against the flange.
The cuts are made with a jig saw and smoothed with a file.
Making these wheels is no gambol!!
Once the parts are all cut and fitted, the construction of the wheel proceeds along these lines:
1. Centre the brake disc over the wheel and screw it on temporarily around a line 1" in from its outer circumference.
2. Centre the spacer hub over the other side of the wheel, and screw and glue it to the wheel.
3. Centre the spoke disc over the hub, and drop the spoke rim on top of it, screwing it down through the spoke disc onto the wheel. The rim is supposed to be 1" in width, the same as the spoke disc's outer ring; but, as noted above, the spoke disc has to negotiate a curve to reach the periphery, so the inner circumference of its outer ring actually falls a little within the inner circumference of the rim. This can clearly be seen on the photo below of the finished car in the plans, and it looks a bit sloppy.
4. Mark all the parts so that they can be located again over the screw holes, and disassemble them again.
5. Fit the tyre over the wheel, by cutting
relieving notches on one
side of it if necessary.
And it is necessary. I got by with three cuts and a hell of a
lot of leverage. You need a hacksaw to get through the wire cable in
the inner beading of the tyre, and something to use as a tyre lever.
The flat spanner I use to put the blades on my table saw was just right
for the job. Some candle wax rubbed onto the rim of the wheel helped
slide the tyre rim over the wood too. The cuts are made on the inside
surface of the tyre, but they do not have to be deep enough to show
around the brake disc. I suppose that is just in case. The inside (and,
therefore, unseen) surface of the tyre is easily determined in
the case of my tyres, which have Chinese characters on them on one
side. Hardly what one would expect of a Bugatti!!
6. Reassemble the parts, centre the tyre and screw down again, gripping the tyre permanently between the brake disc and wheel on the inside, and between the spoke disc and wheel on the other. The plans say to cut relieving kerfs on to underside of the spoke disc to allow it to take the bend, but I found this unnecessary. Gentle and slow clamping was all that was necessary. An occasional superficial surface crack opened up on the outside where the tension was greatest, but they were not a problem. The spoke disc was painted with epoxy resin before getting its final colour, and that soaked into the cracks and bound them down.
Nevertheless, as the final trimming of the spoke disc was done on a router table, it would be easy enough to continue the circumferential cuts on a small router bit to achieve the kerfs which are called for.
It would probably be a good idea to paint the parts before their final assembly, to avoid smudges on the tyre, etc., but after the struggle to get this one tyre on there is no way I am going to take it off again. Perhaps for the other three wheels!
A coat of silver on the spoke disc and ring blends in nicely with the galvanised hex head sheet metal screws, and the antique ivory recommended for the wheel disc
in the plan works well too.
The advantage of making the wheel components the
way I have, on a carousel arrangement through a central spindle, means
that I can be certain that the hole is exactly in the middle, so all I
have to do now is enlarge it to fit the axle and bearing. The wheel is
placed on a drill press, and the small diameter drill which has been
used up to now is run down into the hole to centre the wheel under the
drill. The wheel is clamped into position and the drill bit is changed
for a larger one, up to the 1/2" necessary. With the copper tube
bearing inserted through the enlarged hole, and the outer flange
snugged down over it, holes for the flange bolts can now be drilled
through, and the inner flange can be connected to the bolts and
tightened into position.
The hubs for these wheels consist of the aforementioned flanges, into which are screwed 1/2" male to 1/4" female bushings. The bushings have to be drilled out to accept the 1/2" outside diameter copper tube, into which the axle rods are inserted. 1/2" to 1/4" bushings are not available here. The nearest I could come up with was a 1/2" male to 1/2" capillary union in brass. Apart from the dissimilar metals causing some problems with corrosion, which can be overcome, these seem to be even more useful than the bushings, since they have only a small internal lip to be drilled out to 1/2" in order to have a 1/2" channel all the way through.
The flange, the union and the constructed hub.
Top of Page
The wheel design is such that the total thickness of wood inside the tyre is only 1-1/8", which does not seem much to go inside a 2.125" tyre, but after cutting all these discs I'm not arguing!
What I might argue, however, is the suitability of these wheels in the first place. While they look all very well, I have noticed that the discs have started to warp as soon as they were cut. Perhaps some bicycle wheels would be more practical. If the authentic look is important, laminated wheels made up of three 1/4" ply discs would be more stable. However, I am committed now, so, on to the rims discs...
These can be cut in their circumference while attached to the wheels, so as to ensure that they fit the wheels perfectly. Their attachment to an underlying solid surface also helps prevent splintering of the ply where the blade crosses the grain. In a short time, a full set of wheels and rims are ready.
As long as the inner circumference of the ring is rounded beforehand, the rest can be done on the router table after the ring is glued to the wheel. Just remember to keep the brads which hold the two together out of the path of the router bit. Brads are used at approximately 3" centres to hold the ring onto the wheel, and yellow glue is alright, since this joint will be protected from water by its location inside the tyre.
The purpose of these rims is to reinforce the wheels and to thicken them where they meet the inside of the tyres. The cut out waste is used to manufacture the "brake discs" which attach to the inside of the wheels. These latter members act in concert with the spoke discs on the outside to hold the tyres onto the wheels. There is a discrepancy in the plans regarding the dimension of the brake discs. They are shown to have dimensions of 12-1/2", whereas the instruction says to cut them to 12-1/4". The correct dimension is 12-1/2". The rim discs are 13" inside diameter, so there is only a 1/4" gap between the outside of the brake disc and the inside of the rim, (the two 1/4" making up the 1/2" difference in diameter).
The composite structure now looks like this:
A wheel with its reinforcing disc applied and rounded over.
When it comes time to cut the spoke discs, no actual diameter is given. Instead, a template on the plans is available. (Actually, two templates are given). However, the diameter of both of them is 12-1/4", which can't be right, because they have to be the same as the brake discs. The instruction with one of the templates states: "After drawing outside of pattern and cutting outside of line, dia. should be close the 12-1/2"." Why not make the pattern accurate and cut and draw right on the lines?
Now, the spoke disc is held out from the centre of the wheel by a 3/4" thick hub, and its outer edge is held against the tyre by a ring which is screwed through the spokes and the wheel, clamping the tyre between spoke disc and wheel. The outside diameter of the ring is 12-1/2", so the diameter of the spoke disc should be the same when in position. But because of the hub holding out its centre, this means that it should be cut greater than 12-1/2", not less. If you work it out it should really be cut to a diameter of 12-3/4". Nevertheless, if you have already cut the spoke disc to 12-1/2", as I have, there will only be a discrepancy of less than 1/8" all round, which will be obscured by the tyre anyway, so it does not really matter.
But it is a warning about the dimensions on the plans, especially on the templates. They all need to be double checked before cutting.
The hubs which attach to the outside of the wheels and hold out the spoke discs are to be 3-1/8" in diameter, so that they can accept the fixation of the 3" flanges which support the wheel axles. I have only been able to acquire 4" flanges, so I have to increase the diameter of the hubs accordingly, and also the diameter of the central part of the spoke discs. The spokes on my car will have to be 1/2" shorter than on the Stevensons' car.
The spoke disc is marked up and fitted against the flange.
The cuts are made with a jig saw and smoothed with a file.
Making these wheels is no gambol!!
Incidentally, the diagrams in
the plans show the 3" flanges drilled for four countersunk bolts, which
are 1/4" in diameter. The local flanges,as
can be seen above, are
drilled without countersinking, and the holes are 1/2". So the bolts
which hold the hubs onto the wheels will have to be beefed up to 1/2".
They will be a tight enough fit not to require washers. However, the
proximity of these large holes to the edge of the wooden hubs may make
for a weakness. The rear axle on the non-drive wheel passes through a
hub close to its edge, and the recommendation there is to reinforce it
with a hose clamp. I think that would be a good precaution here too. To
the right you can see the screw fastener of the hose clamp on the hub.
Once the parts are all cut and fitted, the construction of the wheel proceeds along these lines:
1. Centre the brake disc over the wheel and screw it on temporarily around a line 1" in from its outer circumference.
2. Centre the spacer hub over the other side of the wheel, and screw and glue it to the wheel.
3. Centre the spoke disc over the hub, and drop the spoke rim on top of it, screwing it down through the spoke disc onto the wheel. The rim is supposed to be 1" in width, the same as the spoke disc's outer ring; but, as noted above, the spoke disc has to negotiate a curve to reach the periphery, so the inner circumference of its outer ring actually falls a little within the inner circumference of the rim. This can clearly be seen on the photo below of the finished car in the plans, and it looks a bit sloppy.
To overcome that I have cut my
rims 1-1/4" wide
instead of 1". That gives a crisp finish and obscures the spoke ring.
Fussy, I know.
4. Mark all the parts so that they can be located again over the screw holes, and disassemble them again.
6. Reassemble the parts, centre the tyre and screw down again, gripping the tyre permanently between the brake disc and wheel on the inside, and between the spoke disc and wheel on the other. The plans say to cut relieving kerfs on to underside of the spoke disc to allow it to take the bend, but I found this unnecessary. Gentle and slow clamping was all that was necessary. An occasional superficial surface crack opened up on the outside where the tension was greatest, but they were not a problem. The spoke disc was painted with epoxy resin before getting its final colour, and that soaked into the cracks and bound them down.
Nevertheless, as the final trimming of the spoke disc was done on a router table, it would be easy enough to continue the circumferential cuts on a small router bit to achieve the kerfs which are called for.
The spoke disc is
gently, and then firmly, pushed into position, overcorrecting here
because the tyre is not yet on.
It would probably be a good idea to paint the parts before their final assembly, to avoid smudges on the tyre, etc., but after the struggle to get this one tyre on there is no way I am going to take it off again. Perhaps for the other three wheels!
A coat of silver on the spoke disc and ring blends in nicely with the galvanised hex head sheet metal screws, and the antique ivory recommended for the wheel disc
in the plan works well too.
The hubs for these wheels consist of the aforementioned flanges, into which are screwed 1/2" male to 1/4" female bushings. The bushings have to be drilled out to accept the 1/2" outside diameter copper tube, into which the axle rods are inserted. 1/2" to 1/4" bushings are not available here. The nearest I could come up with was a 1/2" male to 1/2" capillary union in brass. Apart from the dissimilar metals causing some problems with corrosion, which can be overcome, these seem to be even more useful than the bushings, since they have only a small internal lip to be drilled out to 1/2" in order to have a 1/2" channel all the way through.
The flange, the union and the constructed hub.
When the
inner
and outer hubs are finally bolted together through the wheel, the
centre of the brake disc is pulled into contact with the wheel. At its
periphery it is held away from the wheel by the tyre. So, it takes on a
concave contour. This may seem wrong, but it is the only way of doing
it with this construction method. By careful alignment, the through
bolts and the central hub unions (or bushings) should all line up
perfectly, and a 1/2" diameter copper tube is inserted through from the
outside union to the inside one, and is trimmed off so that it is just
a little longer than the distance from one union end to the other. In
this way, washers which are later fitted over the axles, ride against
the copper tube, and not against the hubs. The quality of the axle
mechanism depends heavily on the snugness of fit between the inside of
the copper tube and the shank of the bolt which acts as the axle.
Unfortunately, at the moment the inside diameter of the copper tube is
10.8 mm. and the diameter of the shank of the axle bolt is 11.2 mm., so
some adjusting is going to have to happen before the wheels can be
fitted
to the car. The copper tube bearing is only 0.9 mm. thick, so reaming
it is not a practical proposition. Instead, the axle bolt will have to
be machined down to fit. That means that its zinc coating will be lost
and it will rust, so the best option will be to replace the bolts with
stainless steel. 304 stainless is not too expensive.
The completed wheel.
Later, 1/4" ply knock-offs are fixed to the wheels by removing the bushings, or unions, from the flanges, and screwing them back down over the knock-offs. The drive wheel in the rear is a little different from the other three, and the knock-off assembly has to be altered to accommodate it. Basically, the problem is the drive axle stub which is bent over the hub to be bolted onto the wheel. This is done in the instructions before the knock-off is fitted, so, in order to have enough room to slide the knock off over the stub, a 1" hole is cut. This means that the bushing is not able to secure the knock-off to the hub, because the hole is too big, so the knock-off is epoxy glued to the hub instead. I see no reason why the kock-off cannot be put on the hub before the axle is bent onto the wheel. In that case, the hole would be the same as the others and no epoxy would be necessary. You just have to be a bit careful when you bend the axle not to damage the knock-off. Whichever method you use, after fitting they look like this:
Once the wheels are completed they can be put aside while the car body is built.
The completed wheel.
Later, 1/4" ply knock-offs are fixed to the wheels by removing the bushings, or unions, from the flanges, and screwing them back down over the knock-offs. The drive wheel in the rear is a little different from the other three, and the knock-off assembly has to be altered to accommodate it. Basically, the problem is the drive axle stub which is bent over the hub to be bolted onto the wheel. This is done in the instructions before the knock-off is fitted, so, in order to have enough room to slide the knock off over the stub, a 1" hole is cut. This means that the bushing is not able to secure the knock-off to the hub, because the hole is too big, so the knock-off is epoxy glued to the hub instead. I see no reason why the kock-off cannot be put on the hub before the axle is bent onto the wheel. In that case, the hole would be the same as the others and no epoxy would be necessary. You just have to be a bit careful when you bend the axle not to damage the knock-off. Whichever method you use, after fitting they look like this:
Once the wheels are completed they can be put aside while the car body is built.
Top of Page
3. The Chassis
The chassis consists of two side frame rails, joined to a rear cross member placed vertically, and two front cross members placed horizontally which house between them the kingpins for the steering system. It is simple in the extreme, relying on screw and glue technology for its strength. The largest components, the frame rails, are made from 1 x 6 pieces of fir or pine which are cut to shape from the lofting provided by the plan. The second could be shaped from the first with a router and copying bit.
The frame rails with
and without the lightening holes which are supposed to represent the
louvres in the T35.
The original Bugatti T35 had extensive louvres, not only on the hood, but also on the frame where they served no purpose other than decoration. As a nod to the latter, but not to get involved in all the work which would be required in reproducing them, the Stevensons provide a pattern of "lightening holes" 1/4" deep in the rails as a substitute. These are seen above.
After squaring the structure, the glue is applied to the rear cross member and a stiff chassis results.
The chassis after refitting of the front cross members and kingpins.
4. The Steering Components
The cross members are now removed from the chassis, and drilled to accept the kingpins as described in the plans. Even although I used hardwood for these pieces, there was a tendency for them to split as the kingpins were tightened home into them. That is partly because the bushings were rather poorly cast, and sloped outwards at their shoulders, but partly too because of the proximity of the holes to the end of the boards. Only 1/2" of meat to resist a lot of force. I think an extra 1/2" would have helped here; but I was stuck with what I had cut, so I filed down the shoulders of the bushings as best I could, and I will reinforce the areas with epoxy and fibreglass later.
The bushing is flush with the surface of the cross member, and protrudes enough on the other side for the lock nut.
Lock nut applied (left), and the kingpin assembly screwed on (right).
The steering mechanism assembled.
Once the front cross members are mounted back onto the chassis
the rest of the steering components can be fitted. They consist of a
tie rod between the nipples on the back end of the kingpins, and its
connection to the steering column.
The front cross members with kingpins and tie rod. The screws attaching the unit to the chassis have not yet been
countersunk and the ends of the cross members have not yet been rounded.
The wheels are fitted, and fixed with split pins, and hey presto.... a rolling chassis is complete, nearly. It still drags its back end because only the front wheels can be attached.
5. The Drive Train
It is in the instructions for the drive train that the continuation of a number of ambiguities arises. This one relates to the bearing for the axle on the drive wheel. (Only the right hand wheel is driven). For, while the axle must presumably lie at a right angle to the long axis of the car, the bearing on the frame, a floor flange with a brass nipple attached to it, is bolted to the frame rail which is 5° off a right angle. The non-driven left wheel axle is merely bent around to lie in the correct plane, and that does not matter, but the drive wheel's axle cannot be bent. Some of the diagrams in the plans clearly show the bearings mounted in a plane parallel to the body sides, but another shows the axle miraculously emerging through the bearing at right angles to the long axis of the car.
If the crank, which continues to become the drive axle, is connected to both the flange on the drive wheel side frame and another bearing on the opposite frame, then there will be a combined angle of 10º off straight between the its ends. The crank will have to bend on itself 10º for every revolution. What is more, the drive wheel will be bent in towards the car body by 5º. This cannot be desirable, leaving the only possible solution to be a sloppy bearing. If the bearing on the flange on the frame rail is sloppy enough to allow the axle to pass through it in a diagonal manner it could let it come out perpendicular to the long axis.
I think to best solution here would have been to cut wedge shaped spacers to mount snug bearings perpendicular to the long axis, and it would have saved a lot of head scratching if the instructions had suggested that! But that is not what the instructions say, so I will make the system as is is described and see what happens.
The crank is the critical part of this structure. It is 1/2" iron rod which is bent into the correct configuration. Clearly, there is little tolerance for error here if the car is not to shudder or vibrate when being driven. Because of the difficulty the Stevensons had in acquiring iron rod in lengths greater than 36", they call for the axles to be build separately, and for the non-driven wheel to be located a little behind the driven one. They state that if a longer rod can be found then the wheels can lie in the same transverse plane, but if the body has already been constructed you will not be able to fit a single axle, unless there are open slots to fit it into the chassis, rather than holes.
What is readily available here is galvanised mild steel rod, and 48" of it is not a problem. However, it is labelled 12 mm. so may be loose in the bearings if that is an accurate dimension. On measurement, the rod I acquired was 12.5 mm., so 1/2" bearings are perfect for a snug fit on the wheels.
Remember the annoying instruction that plagued the fitting of the front wheel axles? Well, on the rear wheels the set up is as follows: same as the front wheel, with the addition of an extra flange bolted to the frame for the drive axle, and a 1-1/2" brass nipple beyond it so that the wheel is kept away from the body of the car. This is the member which has to be a sloppy fit, so use one which has an inside diameter of 5/8". On the drive wheel itself there is no turning on the axle required, so no copper tube bearing is needed. That is just as well, since the crank/axle is supposed to be 1/2", so there would be no room for a copper bearing inside the 1/2"inside diameter brass bushings. The non-drive wheel does spin on its axle, so does need some sort of bearing, but the bushings themselves may have to serve that purpose, possible using some brass olives to replace the tubing.
The drive wheel is located on the right hand side of the car, and the flange which supports it on the frame rail is specified to be centred 1-1/2" below the top of the rail. My flanges are bigger than the 3" one the Stevensons use, so it has to be 2" below the top of the rail. Otherwise the procedure is the same. The extra half inch may prove to be useful, because it moves the crank an extra half inch down from the seat. It is a tight fit the other way, and the instructions mention that the seat may have to be relieved a bit to allow free movement of the crank. If that is still the case with the new position, the relief will be less extensive.
Measuring for the right side flange.
The revised position of the flange is determined.
6. The Body
Most of the body consists of 1/4" ply A/C exterior grade, but A/B would give a nicer finish on the inside. Some parts are of solid lumber, such as the grill, which is attached at the back of the front cross members. The body sides go inside the chassis frames and outside the grill, and are largely held in position by the seat and seat back, plus the triangular gusset which forms the fish tail rear end. Lofting instructions are straight forward, with just a little complexity introduced by the need to accommodate the 5° flare of the sides of the car. This has already been encountered in the rear cross member of the chassis, but now it has to be applied to the grill, only along that part of its edge which meets the body side. Not too difficult.
The lofting instructions for the body side are simple, and it fits well, apart from the notch for the tie rod which has to be added. But the screws called for are 1 inch. The ply is 1/4" and the chassis rail into which it is being screwed is 3/4", so there is no room for error. Try to ensure that the screw holes do not enter one of the lightening holes which have been bored into the rail, otherwise the screw will poke through into it. The side is not glued on, so that it can be removed later if necessary, but I think a glued side would give a stiffer construction. We'll see...
7. Installing
the
Steering Column
The steering column itself is designated to be made of 3/8" galvanised components, but 1/2" has the advantage of being available. The metric lengths supplied here, and the variation in the dimensions of such thing as adapters, nipples, etc. meant that the fitted column was a little bit short. That difference was made up by lengthening the section of all thread brass which I used to replace the nipples. Basically, the column consists of a 600 mm. pipe screwed into a T at the bottom, which in turn is screwed into a brass all thread, then a cap. The cap is drilled for a 1/4" bolt which passes through the grill, where it is held by washers and nuts.
Seen
on the left is the T, which needs to have a short pipe length added to
it, about 3", and another 5/16" bolt to engage the link on the tie rod.
(This latter bolt has to be threaded all the way to the head so that a
tightening nut on it can lock it on to the nipple. All thread 5/16"
bolts are not readily available, so I substituted a length of 5/16"
threaded rod cut to size. The bolt head will be substituted for by two
locking
nuts).
At the top end, the pipe terminates in a 1/2" to 1/2" socket, another section of all thread and finally a flange, which will ultimately be bolted to the steering wheel.
All the components which might be able to become unscrewed are fixed by drilling small holes for the passage of split pins, and the others are bonded with Thread Lock.
The drilling of a central hole perpendicularly into the dash board was not entirely satisfactory, as it meant that the dash had to be tilted forward for the holes there and in the grill to line up. This, in turn, meant that the box top had to have a 1/4" strip removed from its trailing edge to allow the dash to tilt.
8. Fitting the Rear Wheels
Since the crank has to be made now, there seems to be no reason not to go ahead and fit the rear wheels. The bending of the crank is a lot more difficult than it sounds, and it is a pity to see the hot dip galvanisation, for which you have paid, result in cracked and shedding splinters of zinc where the bends are placed. The exact dimensions given are not critical if you can get a long enough rod, and do away with the double axle system which the Stevensons used. They were unable to get rod longer than 36", but I had no difficulty and used a 48" piece. That meant that there had to be a cut out under one of the rear axle holes in the frame rail to admit the axle, and I did that after the hole had been cut, so that it can be glued back in again later. In the meantime, because there has been some delay in continuing this project, a spell of wet weather has resulted in some mould forming on the ply wood. I felt that it was time to get some paint onto the wood to stop any further deterioration. Here there is a single undercoat layer on the outside.
After sanding the fibreglass is applied to the whole body. Two coats of epoxy are needed for it, followed by more sanding and more filling.
In between sanding and painting jobs I have begun to fit the odds and ends. Here are the exhaust pipe and the hand brake. A spare throttle lever from the slipper launch made up the latter, while the former is merely a chromed pipe inserted into an electrical conduit 90° junction surrounded by bilge hose.
Fitting the aluminium flashing for the grill and bonnet makes a mess of the paintwork, so it is best not left until after the final coat goes on. Here the two aluminium parts are temporarily fitted over the undercoat. They will be replaced and fixed permanently after the top coat is dry.
14. The Finish
After sanding the whole car again, I went for a spray finish. The nearest I could come up with to French racing blue was something called Bermuda blue. It is not too bad. The grill is done according to the Stevensons' recommendation, with black contact paper. After two coats the gadgets were stuck on again, and a makeshift hood hinge was manufactured from half round dowel. Wherever possible the additions are fixed with rivets to avoid any sharp edges inside the body work.
I added some aluminium bar on top of the chassis rails, and a badge bar in front of the grill.
The badge is an authentic Centenary of Bugatti badge, which are still available occasionally today on Ebay.
But, before doing that, I stumbled across some
flush plugs for electric light switch plates, and they are just the
right size to fill those vaguely ridiculous spade bit holes in the
chassis rails. The plugs squeeze into the holes left by the central
spur of the bit, and give the car a more exotic look to boot. It still
won't stop people asking what those holes are for. It is the commonest
question I have had about the project so far.
A piece of offcut suedette provided the cushion cover for the seat back, wrapped around three inch foam and tacked onto a ply former. Some black rubber door seal moulding protects from the sharp edges of the cockpit sides, but behind the seat and around the dash and cowl it has to be changed to self adhesive foam rubber draught excluder.
The Stevenson plan calls for an optional adjustable seat to allow for different sized drivers, but this car is for one child only, and he can grow into it. A cushion for the seat pan might be a nice idea, although none is called for in the original.
Some chromed flanges make dashboard dial faces, with some black contact paper behind them to exclude the silver of the dash itself.
With the seat pan upholstered, only the glazing
remains to be done, then the fitting of the knock-offs, and the bending
of the drive axle to fix to the drive wheel, and this car will be ready
for Christmas.
Almost ready to join the big boys' club.
The time taken was just short of two years, but it
was only intermittent work. It could be managed in a few weeks of
non-stop attention. The cost? Probably close to A$1000, without labour
or delivery charges.
There will be one more set of photos going up on this page showing the car being received by its new owner, and that will possibly answer the question as to whether it was worth all the effort.
The reception may have been more rapturous if he could reach the pedals!
In the meantime, to give me
something to do on the side while I am
building my next boat, I have ordered the Stevenson plans for their old
pedal biplane. That will keep me occupied while the marine epoxy
is drying.
The front cross members with kingpins and tie rod. The screws attaching the unit to the chassis have not yet been
countersunk and the ends of the cross members have not yet been rounded.
The tie rod requires a notch to
be cut into the chassis frame to accommodate its forward and backward
movement as the steering wheel is rotated. The notch is initially
specified to be 3/4" deep, but the actual position of the rod may make
a deeper recess necessary, as in this case. The notch seen here is
3/4", but the rod is chafing against it, so it needs to be cut deeper.
Bearing in mind that the body side will be fixed to the inside of the
chassis, I am not too concerned about weakening the chassis by
deepening the notch
The wheels are fitted, and fixed with split pins, and hey presto.... a rolling chassis is complete, nearly. It still drags its back end because only the front wheels can be attached.
5. The Drive Train
It is in the instructions for the drive train that the continuation of a number of ambiguities arises. This one relates to the bearing for the axle on the drive wheel. (Only the right hand wheel is driven). For, while the axle must presumably lie at a right angle to the long axis of the car, the bearing on the frame, a floor flange with a brass nipple attached to it, is bolted to the frame rail which is 5° off a right angle. The non-driven left wheel axle is merely bent around to lie in the correct plane, and that does not matter, but the drive wheel's axle cannot be bent. Some of the diagrams in the plans clearly show the bearings mounted in a plane parallel to the body sides, but another shows the axle miraculously emerging through the bearing at right angles to the long axis of the car.
If the crank, which continues to become the drive axle, is connected to both the flange on the drive wheel side frame and another bearing on the opposite frame, then there will be a combined angle of 10º off straight between the its ends. The crank will have to bend on itself 10º for every revolution. What is more, the drive wheel will be bent in towards the car body by 5º. This cannot be desirable, leaving the only possible solution to be a sloppy bearing. If the bearing on the flange on the frame rail is sloppy enough to allow the axle to pass through it in a diagonal manner it could let it come out perpendicular to the long axis.
I think to best solution here would have been to cut wedge shaped spacers to mount snug bearings perpendicular to the long axis, and it would have saved a lot of head scratching if the instructions had suggested that! But that is not what the instructions say, so I will make the system as is is described and see what happens.
The crank is the critical part of this structure. It is 1/2" iron rod which is bent into the correct configuration. Clearly, there is little tolerance for error here if the car is not to shudder or vibrate when being driven. Because of the difficulty the Stevensons had in acquiring iron rod in lengths greater than 36", they call for the axles to be build separately, and for the non-driven wheel to be located a little behind the driven one. They state that if a longer rod can be found then the wheels can lie in the same transverse plane, but if the body has already been constructed you will not be able to fit a single axle, unless there are open slots to fit it into the chassis, rather than holes.
What is readily available here is galvanised mild steel rod, and 48" of it is not a problem. However, it is labelled 12 mm. so may be loose in the bearings if that is an accurate dimension. On measurement, the rod I acquired was 12.5 mm., so 1/2" bearings are perfect for a snug fit on the wheels.
Remember the annoying instruction that plagued the fitting of the front wheel axles? Well, on the rear wheels the set up is as follows: same as the front wheel, with the addition of an extra flange bolted to the frame for the drive axle, and a 1-1/2" brass nipple beyond it so that the wheel is kept away from the body of the car. This is the member which has to be a sloppy fit, so use one which has an inside diameter of 5/8". On the drive wheel itself there is no turning on the axle required, so no copper tube bearing is needed. That is just as well, since the crank/axle is supposed to be 1/2", so there would be no room for a copper bearing inside the 1/2"inside diameter brass bushings. The non-drive wheel does spin on its axle, so does need some sort of bearing, but the bushings themselves may have to serve that purpose, possible using some brass olives to replace the tubing.
The drive wheel is located on the right hand side of the car, and the flange which supports it on the frame rail is specified to be centred 1-1/2" below the top of the rail. My flanges are bigger than the 3" one the Stevensons use, so it has to be 2" below the top of the rail. Otherwise the procedure is the same. The extra half inch may prove to be useful, because it moves the crank an extra half inch down from the seat. It is a tight fit the other way, and the instructions mention that the seat may have to be relieved a bit to allow free movement of the crank. If that is still the case with the new position, the relief will be less extensive.
Measuring for the right side flange.
The revised position of the flange is determined.
When positioning the
holes on the flange vis à vis the frame rail, it is better to
use the arrangement above, (ie. holes at 12, 3, 6 and 9 o'clock)
because the ply body is attached to the
inside of the rail, and stops a short distance above the rail's bottom
edge. The lowest flange hole in the position shown above will miss the
body altogether, and the other three will penetrate it. To avoid
binding of the axle on the rail and body a 7/8" or 1" centre hole is
drilled here which allows the 1/2" axle to pass through unimpeded. But
on the left hand side of the car the flange has an extra hole cut into
it to allow the stationary axle to penetrate it 1" behind the flange
centre in a horizontal plane. That means that there is no choice as to
where the holes are positioned, and you just have to cope.
There is one other potentially tight spot for the crank, at the cross member joining the two frame rails behind. If the rear wheels are too far back, or the crank too wide, it will hit the cross member, and there is a limit as to how much that structure can be reduced. So, it is better to err on the small side when bending the crank, to try and avoid this problem.
There is one other potentially tight spot for the crank, at the cross member joining the two frame rails behind. If the rear wheels are too far back, or the crank too wide, it will hit the cross member, and there is a limit as to how much that structure can be reduced. So, it is better to err on the small side when bending the crank, to try and avoid this problem.
6. The Body
Most of the body consists of 1/4" ply A/C exterior grade, but A/B would give a nicer finish on the inside. Some parts are of solid lumber, such as the grill, which is attached at the back of the front cross members. The body sides go inside the chassis frames and outside the grill, and are largely held in position by the seat and seat back, plus the triangular gusset which forms the fish tail rear end. Lofting instructions are straight forward, with just a little complexity introduced by the need to accommodate the 5° flare of the sides of the car. This has already been encountered in the rear cross member of the chassis, but now it has to be applied to the grill, only along that part of its edge which meets the body side. Not too difficult.
The lofting instructions for the body side are simple, and it fits well, apart from the notch for the tie rod which has to be added. But the screws called for are 1 inch. The ply is 1/4" and the chassis rail into which it is being screwed is 3/4", so there is no room for error. Try to ensure that the screw holes do not enter one of the lightening holes which have been bored into the rail, otherwise the screw will poke through into it. The side is not glued on, so that it can be removed later if necessary, but I think a glued side would give a stiffer construction. We'll see...
The second side is the same as
the first, and the grill slots in between the two sides with a 5°
bevel angle cut on it where the two components meet. This is not easy
where the sides begin to curve around the domed part of the grill, but
luckily they do not extend as far around the grill as the drawing would
suggest. (The plan shows a side of 10-3/4" width, whereas it is really
only 9-7/8"). That is a good thing, because there is no provision in
the design of the box top to accommodate an in-curving side, although,
as it sits on top of the sides and not within them, it could easily
enough be planed to fit anyway. It is just that its supporting cleats
(or gussets as they are called in the plans) would have to conform to
the curve.
However, there is a major
problem in the plans from here on: the dimensions given for the box top
seem to be too big, in so far as the width of the box top at the base
is greater than the width of the frame rails at the same level That is
not too much of a problem, because the excess can
be planed off in situ, but the dimensions for the seat seem to be
too big too,
and that cannot be planed. In fact, the widths given for the back end
of the box top, and the front of the seat are exactly the same, but the
seat lies 8" behind the box top. That cannot be the case for a body
which is conical in plan view, as the frame rails are. So, it appears
that the body panels
are to be pushed out at the front end of the cabin at the top, but
remain attached to the frame rails, thus giving an outward and upward
flare to the cabin.
(Later on, when the dashboard is fitted, its dimensions confirm this assumption as the intended one, but there is no mention of this in the plans). I assumed that the body panels would remain straight until they reached the area of the kerfs at the seat back level. If they do not, and the body is supposed to flare, then the cleats which attach the box top to the sides would be more widely spaced apart than the frame rails near the dashboard, but this is not the case in figure 7, where they are shown to be parallel to the rails all along their length.
The diagram from figure 7 clearly showing the cleats running parallel to the frame rails.
Anyway, having decided that there must be a
mistake in the plans, I cut a box top to fit the straight side, and
adjusted the seat dimensions to fit in as well. It was only later when
cutting the dashboard that I realised the problem, and by then it was
too late.
Here, the cleats are screwed on to the sides, ready to accept the box top.
(Later on, when the dashboard is fitted, its dimensions confirm this assumption as the intended one, but there is no mention of this in the plans). I assumed that the body panels would remain straight until they reached the area of the kerfs at the seat back level. If they do not, and the body is supposed to flare, then the cleats which attach the box top to the sides would be more widely spaced apart than the frame rails near the dashboard, but this is not the case in figure 7, where they are shown to be parallel to the rails all along their length.
The diagram from figure 7 clearly showing the cleats running parallel to the frame rails.
Here, the cleats are screwed on to the sides, ready to accept the box top.
Now the diminished top is added,
and planed
flush with the sides
After taking measurements for
the seat, and adjusting the dimensions in the plans for a straight
side, the platform is fitted onto its
supporting cleats, but another anomaly is demonstrated. The back end of
the seat platform is cut back to allow for the boat shaped tail to be
formed, but its width at the back is less than the width of the
triangular boat bottom piece which determines the final shape of the
rear end of the car. So, the sides do not touch the seat at all behind
its widest part. How peculiar!
The seat platform with its cut-in rear end.
The triangular bottom piece is wider than the back of the seat.
Even more puzzling is the lack of instruction to cut the leading edge of the boat bottom on an angle so that it can be attached to the rear cross member and point up towards the back, as the body itself does. Admittedly, it will make the screwing very cramped, but that is better than merely wrenching the bottom piece up to meet the side, as the plan seems to demand. In the end I cut a 7° bevel on the edge, and screwed the piece on from the cross member. It will be glued later as well.
At this stage I have not kerfed the insides
of the side pieces, as is recommended, to take the curve, but it seems
likely that there will be no way to avoid it. The 1/4" ply is quite
stiff and would be likely to snap if I tried to bend it that severely.
So the next step is to unscrew the whole assembly and put in the kerfs.
Then screw it back up again, this time with glue where necessary.
Kerfing the plywood is easy with a table saw. A few trial passes with scrap sets the depth. With the seat in position each panel is bent around the bottom piece and screwed in.
Once that is in position it is merely a
matter of placing cleats for the seat back
on the seat back itself and on the seat
platform. The plans do not mention bevelling
them, but once again it is helpful to do so. Even so, the cleats
attached to the seat back itself are straight, and do not sit easily
inside the body which is curving, so extra fill will be necessary to
close the gaps at some stage. The front of the seat back should line up with the beginning of the scallop
in the body side. If it does not it may be necessary to shave a little
off the appropriate side. A curved sole spokeshave is quite good for
the job, although it does not like ply wood very much.
The gap between the side and the cleat is seen here.
All that now remains of the body construction is a support block to go on to the tail wedge to support the reinforcement for the boot, the reinforcement itself, and the dashboard.
The plan calls for the triangular support brace to be screwed to the seat back via screws from the back into the "edge grain" of the brace. I think a better scheme is to screw a cleat onto the seat back, and the brace onto the cleat, so as to avoid screwing into what would actually be end grain.
Cleats for the brace on the back of the seat and the tail wedge.
The brace is now screwed and glued onto the cleats, and the top of the seat back is planed to the same plane as the brace, so that the aluminium flashing which makes up the top of the body will have a smooth transition from brace to seat.
The final component, the dashboard, is cut to fit between the upturned sides at the cabin front. The outline which should be copied in the plan results in a dashboard 15-3/4" wide. That is far too big to fit into the car I have built. In fact, even in the car dimensions provided in the plans it would be too big. The width of the base of the box top is supposed to be 15-1/4", and the dashboard has to be 1/2" narrower than that to fit between the side panels. So, I cut one to fit my car, but it is not really wide enough to allow for the four dial faces shown on the diagram. Only two are cut. There is a 7/8" hole cut in the centre of the dashboard for the steering column, but with it comes yet another anomaly:
On the template the instruction is to drill it squarely in, and angle the dashboard forward to lie perpendicular to the steering column, but in the instructions it says that in cutting the 7/8" it hole should be angled down towards the steering column hole in the grill. I chose the former method, and marked on the back of the grill the point defined in the plans to locate the steering column's hole. With the aid of a long piece of dowel threaded through the dash and touching the mark on the grill I was able to angle the dashboard appropriately before screwing into it with a single screw from both sides, so that minor adjustments can be made later if necessary.
The dash is fitted and a mark is made on the back of the grill.
The dowel helps in angling the dash correctly.
So, now I have a car body. It is probably narrower in the cabin than it is supposed to be, and it remains to be seen whether this will cause any cramping of little legs is due course. If it does, a new seat, dash and box top will solve the problem. Unfortunately, it also means that some of the other dimensions will be out as well, such as the cut-outs for the aluminium flashing. But as that will have to be trimmed anyway it is not a major problem.
The seat platform with its cut-in rear end.
The triangular bottom piece is wider than the back of the seat.
Even more puzzling is the lack of instruction to cut the leading edge of the boat bottom on an angle so that it can be attached to the rear cross member and point up towards the back, as the body itself does. Admittedly, it will make the screwing very cramped, but that is better than merely wrenching the bottom piece up to meet the side, as the plan seems to demand. In the end I cut a 7° bevel on the edge, and screwed the piece on from the cross member. It will be glued later as well.
At this stage I have not kerfed the insides
of the side pieces, as is recommended, to take the curve, but it seems
likely that there will be no way to avoid it. The 1/4" ply is quite
stiff and would be likely to snap if I tried to bend it that severely.
So the next step is to unscrew the whole assembly and put in the kerfs.
Then screw it back up again, this time with glue where necessary.Kerfing the plywood is easy with a table saw. A few trial passes with scrap sets the depth. With the seat in position each panel is bent around the bottom piece and screwed in.
When both sides are bent around
a truncated triangular wedge is placed between the two back ends to
stabilise the structure, and to later support the reinforcing strip
which runs between the seat back and the tail.
Once that is in position it is merely a
matter of placing cleats for the seat back
on the seat back itself and on the seat
platform. The plans do not mention bevelling
them, but once again it is helpful to do so. Even so, the cleats
attached to the seat back itself are straight, and do not sit easily
inside the body which is curving, so extra fill will be necessary to
close the gaps at some stage. The front of the seat back should line up with the beginning of the scallop
in the body side. If it does not it may be necessary to shave a little
off the appropriate side. A curved sole spokeshave is quite good for
the job, although it does not like ply wood very much.The gap between the side and the cleat is seen here.
All that now remains of the body construction is a support block to go on to the tail wedge to support the reinforcement for the boot, the reinforcement itself, and the dashboard.
The plan calls for the triangular support brace to be screwed to the seat back via screws from the back into the "edge grain" of the brace. I think a better scheme is to screw a cleat onto the seat back, and the brace onto the cleat, so as to avoid screwing into what would actually be end grain.
Cleats for the brace on the back of the seat and the tail wedge.
The brace is now screwed and glued onto the cleats, and the top of the seat back is planed to the same plane as the brace, so that the aluminium flashing which makes up the top of the body will have a smooth transition from brace to seat.
The final component, the dashboard, is cut to fit between the upturned sides at the cabin front. The outline which should be copied in the plan results in a dashboard 15-3/4" wide. That is far too big to fit into the car I have built. In fact, even in the car dimensions provided in the plans it would be too big. The width of the base of the box top is supposed to be 15-1/4", and the dashboard has to be 1/2" narrower than that to fit between the side panels. So, I cut one to fit my car, but it is not really wide enough to allow for the four dial faces shown on the diagram. Only two are cut. There is a 7/8" hole cut in the centre of the dashboard for the steering column, but with it comes yet another anomaly:
On the template the instruction is to drill it squarely in, and angle the dashboard forward to lie perpendicular to the steering column, but in the instructions it says that in cutting the 7/8" it hole should be angled down towards the steering column hole in the grill. I chose the former method, and marked on the back of the grill the point defined in the plans to locate the steering column's hole. With the aid of a long piece of dowel threaded through the dash and touching the mark on the grill I was able to angle the dashboard appropriately before screwing into it with a single screw from both sides, so that minor adjustments can be made later if necessary.
The dash is fitted and a mark is made on the back of the grill.
The dowel helps in angling the dash correctly.
So, now I have a car body. It is probably narrower in the cabin than it is supposed to be, and it remains to be seen whether this will cause any cramping of little legs is due course. If it does, a new seat, dash and box top will solve the problem. Unfortunately, it also means that some of the other dimensions will be out as well, such as the cut-outs for the aluminium flashing. But as that will have to be trimmed anyway it is not a major problem.
The steering column itself is designated to be made of 3/8" galvanised components, but 1/2" has the advantage of being available. The metric lengths supplied here, and the variation in the dimensions of such thing as adapters, nipples, etc. meant that the fitted column was a little bit short. That difference was made up by lengthening the section of all thread brass which I used to replace the nipples. Basically, the column consists of a 600 mm. pipe screwed into a T at the bottom, which in turn is screwed into a brass all thread, then a cap. The cap is drilled for a 1/4" bolt which passes through the grill, where it is held by washers and nuts.
Seen
on the left is the T, which needs to have a short pipe length added to
it, about 3", and another 5/16" bolt to engage the link on the tie rod.
(This latter bolt has to be threaded all the way to the head so that a
tightening nut on it can lock it on to the nipple. All thread 5/16"
bolts are not readily available, so I substituted a length of 5/16"
threaded rod cut to size. The bolt head will be substituted for by two
locking
nuts).At the top end, the pipe terminates in a 1/2" to 1/2" socket, another section of all thread and finally a flange, which will ultimately be bolted to the steering wheel.
All the components which might be able to become unscrewed are fixed by drilling small holes for the passage of split pins, and the others are bonded with Thread Lock.
The drilling of a central hole perpendicularly into the dash board was not entirely satisfactory, as it meant that the dash had to be tilted forward for the holes there and in the grill to line up. This, in turn, meant that the box top had to have a 1/4" strip removed from its trailing edge to allow the dash to tilt.
8. Fitting the Rear Wheels
Since the crank has to be made now, there seems to be no reason not to go ahead and fit the rear wheels. The bending of the crank is a lot more difficult than it sounds, and it is a pity to see the hot dip galvanisation, for which you have paid, result in cracked and shedding splinters of zinc where the bends are placed. The exact dimensions given are not critical if you can get a long enough rod, and do away with the double axle system which the Stevensons used. They were unable to get rod longer than 36", but I had no difficulty and used a 48" piece. That meant that there had to be a cut out under one of the rear axle holes in the frame rail to admit the axle, and I did that after the hole had been cut, so that it can be glued back in again later. In the meantime, because there has been some delay in continuing this project, a spell of wet weather has resulted in some mould forming on the ply wood. I felt that it was time to get some paint onto the wood to stop any further deterioration. Here there is a single undercoat layer on the outside.
The cut-out appears
on the left frame rail.
Using bushings with
5/8" holes on the flanges on the frames allows the crank to extend
through both flanges and maintain perpendicularity to the centre line
of the car, without allowing too much slop.
Showing the crank/axle complex emerging at an angle to the frame.
Once the bonnet has been glued down,
the screws are removed, and the gap between the aluminium and the ply
body side is filled with fairing compound. This one is epoxy thickened
with Microlight. The aluminium is sanded to give some tooth to the
epoxy resin for the fibreglassing.
The fairing compound before it is sanded back (left), and the sanding job on the bonnet (right).
Showing the crank/axle complex emerging at an angle to the frame.
The rear wheels do
not use copper tube bearings like the front ones. The 12.5 mm. axles
make a good fit with unions which are bored out to 1/2". Besides, the
right hand drive wheel does not spin on its bearing. More length of rod
is left for the right side, as it has to be bent back to be fixed to
the wheel later.
9. The Pedal System
On the under-side of the box top is screwed and glued a mounting block for the pedal hangers. The hangers themselves are positioned such that the pedals and the drive mechanism can move clear of the car body, so that has had to wait until the crank and rods were ready to be fitted.
The position for the screws for the mounting block is related to the block's distance from the radiator.
The pedals are made of 5/16" steel rod, but that is not easily found, so I substituted threaded rod, with mixed results. The threaded stuff is more brittle than the unthreaded, and two of them snapped as I was bending them to the required shape. Nevertheless, eventually a hanger is fashioned which supports a foot rod of galvanised pipe, which connects to a drive rod which moves the crank. The critical factor here is fitting the hanger so that it does not hit the side of the body or the steering column.
The drive rods and the pedal hangers.
On the under-side of the box top is screwed and glued a mounting block for the pedal hangers. The hangers themselves are positioned such that the pedals and the drive mechanism can move clear of the car body, so that has had to wait until the crank and rods were ready to be fitted.
The position for the screws for the mounting block is related to the block's distance from the radiator.
The pedals are made of 5/16" steel rod, but that is not easily found, so I substituted threaded rod, with mixed results. The threaded stuff is more brittle than the unthreaded, and two of them snapped as I was bending them to the required shape. Nevertheless, eventually a hanger is fashioned which supports a foot rod of galvanised pipe, which connects to a drive rod which moves the crank. The critical factor here is fitting the hanger so that it does not hit the side of the body or the steering column.
The drive rods and the pedal hangers.
While it
is possible to squeeze in a tight fit for the hanger with some
judicious bending, it proves to be more difficult to avoid the steering
mechanism. Because of the metrication of tubing lengths here, I had to
lengthen the steering column with a piece of brass all-thread. This has
resulted in a clash between the pedal and the T-extension from the
column. The 4" pipe length I used, to replace the 3" nipple which was
specified, now has to be shortened.
The short pipe had to be reduced to miss the pedal hanger, but even then it still hit.
The short pipe had to be reduced to miss the pedal hanger, but even then it still hit.
A
second
shortening fixed the problem.
Apart
from
a slight friction on the bottom of the body when the pedal is
fully extended forward, the drive mechanism now works freely.
10. Hood
and Bonnet
This section should be delayed until you have finished turning the car upside down, as the fragile bonnet and rear deck will be damaged.
To achieve the rounded look of the hood and bonnet of the original cars the plans call for aluminium flashing sheets to be used to form them. Flashing these days is mostly found in rolls of narrow strips, but sheet aluminium can be found, albeit only about half a millimetre thick, which makes the likelihood of future dents almost inevitable. That is especially so on the bonnet which is entirely unsupported along its length. The plan does not state what thickness of sheeting they were expecting to be used, so I assume that the standard sheeting is the one.
Firstly, it is necessary to plane down the top of the dashboard so that the aluminium sheet has a flat surface to fix to, rather than an edge. (That has already been done on the seat back). For reasons explained below, it is not necessary to plane a flat all around the dash, because the hood breaks off contact with it peripherally.
Then, the grill trim has to be added. This is a bizarre structure of "soft aluminium moulding for ply wood", a simple lipped edge which is wrapped around the grill to leave the lip hugging the grill front and give it a clean metallic line. Now, goodness knows what they have in the USA which allows that to happen without causing the lip to buckle as it is forced around the tight radius; whatever it is, it doesn't seem to exist here. I had to start with a moulding with a half inch lip, which I cut down to 1/4", or 6 mm. Then with one end clamped to the grill front where it is intersected by the upper front cross member, the moulding was gradually pushed up against the perimeter of the grill towards its apex.
Similar practical considerations apply to the rear
deck. Its front lip is initially hammered over the front of the seat
back, where it will be filed off flush after the glue is set. Any
fixations such as staples can be left here, as it will be covered by
the seat back cushion and the cockpit padding which goes on later. The
back end, where the wedge shaped tail has to be rounded to allow the
aluminium to "drape" over it, is a bit
messy. The stuff definitely does not drape. It has to be trimmed and
tucked, and will need plenty of filler later to make it smooth again.
Rear deck in place.
However, with the second pedal
in place it becomes obvious that the narrowed body on this car is going
to cause a problem. There is barely enough room for the pedal hangers
to pass one another in the middle, and a small deviation in direction
from the peddler will make them lock up. There is a bit to spare on the
side, so even an extra half inch or so in width for the hanger blocks
to be mounted might make a more comfortable clearance. The hangers have
already had to be bent around the steering column so that they do not
bump into it.
The question then is whether to
start the body over and make it the way it was intended. That will have
to be decided before the hood is attached. To do so would require a new
box top, seat bottom and dashboard. Bearing in mind that the hangers
come closest to one another at the bottom, where the frame shape would
not be altered, there may be only a tiny bit of difference, and it
could only be realised by altering all the angles in the hangers. All
this metal bending is a thorough pain, as I am not well equipped for
metal work, so I am loath to start it again.
I may even consider whether a bicycle chain drive would not be a better alternative to this crank system.
I may even consider whether a bicycle chain drive would not be a better alternative to this crank system.
This section should be delayed until you have finished turning the car upside down, as the fragile bonnet and rear deck will be damaged.
To achieve the rounded look of the hood and bonnet of the original cars the plans call for aluminium flashing sheets to be used to form them. Flashing these days is mostly found in rolls of narrow strips, but sheet aluminium can be found, albeit only about half a millimetre thick, which makes the likelihood of future dents almost inevitable. That is especially so on the bonnet which is entirely unsupported along its length. The plan does not state what thickness of sheeting they were expecting to be used, so I assume that the standard sheeting is the one.
Firstly, it is necessary to plane down the top of the dashboard so that the aluminium sheet has a flat surface to fix to, rather than an edge. (That has already been done on the seat back). For reasons explained below, it is not necessary to plane a flat all around the dash, because the hood breaks off contact with it peripherally.
Then, the grill trim has to be added. This is a bizarre structure of "soft aluminium moulding for ply wood", a simple lipped edge which is wrapped around the grill to leave the lip hugging the grill front and give it a clean metallic line. Now, goodness knows what they have in the USA which allows that to happen without causing the lip to buckle as it is forced around the tight radius; whatever it is, it doesn't seem to exist here. I had to start with a moulding with a half inch lip, which I cut down to 1/4", or 6 mm. Then with one end clamped to the grill front where it is intersected by the upper front cross member, the moulding was gradually pushed up against the perimeter of the grill towards its apex.
Whereas the grill was to be cut
so that the body sides remained flush with the grille's perimeter, by
using a rebate, unfortunately no such refinement was ordained for the
dashboard. The result is that the dash sits entirely within the body,
but the hood is attached to its outside. So, the hood departs the
support of the dash on the side and opens up a small triangular
gap. This is an invitation to a major dent, and being so close to the
cockpit, is a trap for little fingers. The gap should be filled. As I
am using epoxy frequently I propose to put a plug of it into this gap,
and I think that it would not be a bad idea to fibreglass the hood as
well, to make it more dent resistant.
Demonstrating the gap between the aluminium flashing of the hood and the dashboard.
Incidentally, the natural inclination in attaching the hood would be to cut it flush with the back of the dash, but, although the plan does not say so here, it is intended that a rubber moulding should be put around the sharp edges of the cockpit, including the hood, so you could leave a little jutting back for the moulding to fit on to later.
The procedure for making up the bonnet is to drape the roughly cut aluminium over the radiator and dashboard, fix it firmly front and back so that it overlaps the top of the body box by 1/2", and then do the same on the other side. The edges of the aluminium are stapled along the body, and the join is filled with automotive putty and sanded smooth. There is no template given for the hood or the rear deck, but that is no hardship, especially on my car whose front is a different shape anyway. There are dimensions given for later trimming, and these can be adapted to the shape of the car as you have it.
The staples for the bonnet pass through the aluminium and the body ply, and into the cleats which support the box top. With the rear deck there is no line of cleats to use, so the recommendation is the staples not be used, as they have nothing substantial to grip. Instead, pop rivets are employed.
The shape of the tail wedge and rear panels has to be rounded so that the aluminium of the rear deck can be smoothed over them.
In view of the fragility of the bonnet, I have decided to reinforce it with fibreglass and epoxy resin. Since I am going to be using epoxy anyway, I might as well glue the bonnet down with it, and fair with it also. Therefore, I used screws instead of staples. They are easier to remove after the epoxy has set. Incidentally, cutting aluminium flashing is no joke either. Along the sides of the bonnet I did it on my table saw and achieved a smooth cut, but along the front and dash areas, where it had to be done with snips, the line was jagged and irregular. There I just hammered the excess over the edges and filed it smooth. So much for leaving a lip jutting into the cockpit.
The bonnet is screwed on.
Demonstrating the gap between the aluminium flashing of the hood and the dashboard.
Incidentally, the natural inclination in attaching the hood would be to cut it flush with the back of the dash, but, although the plan does not say so here, it is intended that a rubber moulding should be put around the sharp edges of the cockpit, including the hood, so you could leave a little jutting back for the moulding to fit on to later.
The procedure for making up the bonnet is to drape the roughly cut aluminium over the radiator and dashboard, fix it firmly front and back so that it overlaps the top of the body box by 1/2", and then do the same on the other side. The edges of the aluminium are stapled along the body, and the join is filled with automotive putty and sanded smooth. There is no template given for the hood or the rear deck, but that is no hardship, especially on my car whose front is a different shape anyway. There are dimensions given for later trimming, and these can be adapted to the shape of the car as you have it.
The staples for the bonnet pass through the aluminium and the body ply, and into the cleats which support the box top. With the rear deck there is no line of cleats to use, so the recommendation is the staples not be used, as they have nothing substantial to grip. Instead, pop rivets are employed.
The shape of the tail wedge and rear panels has to be rounded so that the aluminium of the rear deck can be smoothed over them.
In view of the fragility of the bonnet, I have decided to reinforce it with fibreglass and epoxy resin. Since I am going to be using epoxy anyway, I might as well glue the bonnet down with it, and fair with it also. Therefore, I used screws instead of staples. They are easier to remove after the epoxy has set. Incidentally, cutting aluminium flashing is no joke either. Along the sides of the bonnet I did it on my table saw and achieved a smooth cut, but along the front and dash areas, where it had to be done with snips, the line was jagged and irregular. There I just hammered the excess over the edges and filed it smooth. So much for leaving a lip jutting into the cockpit.
The bonnet is screwed on.
Rear deck in place.
In the meantime, I
dry fitted the louvres. They should open back rather than down, but
they were just the right size as they were, so I left it. They will
have to be removed again for the epoxy and paint work, and then
refitted with rivets rather than screws, because they are into the ply
sides.
The fairing compound before it is sanded back (left), and the sanding job on the bonnet (right).
After sanding the fibreglass is applied to the whole body. Two coats of epoxy are needed for it, followed by more sanding and more filling.
11. The Steering Wheel
While all this is going on the steering wheel was fashioned. Despite the narrower cockpit and dashboard than I should have had, I decided to cut the wheel to the original size, except that the central disc is cut to fit the four inch flanges which I have, instead of the three inch ones which were called for. The grips are wrapped in nylon cord to simulate the linen binding of the old cars. And a small Bugatti pin badge was glued into the centre of the wheel.
While all this is going on the steering wheel was fashioned. Despite the narrower cockpit and dashboard than I should have had, I decided to cut the wheel to the original size, except that the central disc is cut to fit the four inch flanges which I have, instead of the three inch ones which were called for. The grips are wrapped in nylon cord to simulate the linen binding of the old cars. And a small Bugatti pin badge was glued into the centre of the wheel.
In between sanding and painting jobs I have begun to fit the odds and ends. Here are the exhaust pipe and the hand brake. A spare throttle lever from the slipper launch made up the latter, while the former is merely a chromed pipe inserted into an electrical conduit 90° junction surrounded by bilge hose.
Fitting the aluminium flashing for the grill and bonnet makes a mess of the paintwork, so it is best not left until after the final coat goes on. Here the two aluminium parts are temporarily fitted over the undercoat. They will be replaced and fixed permanently after the top coat is dry.
I thought for a while about
centring the screen, because it looks peculiar to have it over to the
right in a one seater, but what the hell...let's go for head turning!
The cowl had to be cut shorter than the outline given with the plan,
because of the narrower cockpit which I produced. And it sits a little
higher than it probably should too. The instructions are to attach it
with two only sheet metal screws, but that leaves it flapping about in
the middle, so I used a line of rivets as well.
A line of rivets holds the cowl on.
A line of rivets holds the cowl on.
The joint with the hood has to
be filled with auto putty anyway, so that makes the rivets easy to
hide. Their tops will be sanded away with the excess
putty.
The eccentric cowl is puttied to the bonnet.
The eccentric cowl is puttied to the bonnet.
The windscreen
itself is a piece of Perspex, cut to fit into a frame which is bolted
to a fixture on the cowl. As I am making these pieces up I am also
painting the car, so the colours seen here are a bit out of order. The
cowl fixture is made of small aluminium angle, cut and bent around the
cowl, and riveted to it.
14. The Finish
After sanding the whole car again, I went for a spray finish. The nearest I could come up with to French racing blue was something called Bermuda blue. It is not too bad. The grill is done according to the Stevensons' recommendation, with black contact paper. After two coats the gadgets were stuck on again, and a makeshift hood hinge was manufactured from half round dowel. Wherever possible the additions are fixed with rivets to avoid any sharp edges inside the body work.
I added some aluminium bar on top of the chassis rails, and a badge bar in front of the grill.
The badge is an authentic Centenary of Bugatti badge, which are still available occasionally today on Ebay.
Another badge, this
time a pin badge in plastic, fills in a missing detail. A self adhesive
furniture leg protector makes the radiator cap.
With all the gadgets
in place again it is now time to set about painting the inside of the
car and making the seat cushion.
A piece of offcut suedette provided the cushion cover for the seat back, wrapped around three inch foam and tacked onto a ply former. Some black rubber door seal moulding protects from the sharp edges of the cockpit sides, but behind the seat and around the dash and cowl it has to be changed to self adhesive foam rubber draught excluder.
A second bonnet hold down strap
acts to protect against the sharp edge of the aluminium hood moulding,
and some more adhesive protectors are applied to the dumb iron, mainly
to cover up some imperfections in the surface of the epoxy coated metal
rather than for any justifiable purpose.
The Stevenson plan calls for an optional adjustable seat to allow for different sized drivers, but this car is for one child only, and he can grow into it. A cushion for the seat pan might be a nice idea, although none is called for in the original.
Some chromed flanges make dashboard dial faces, with some black contact paper behind them to exclude the silver of the dash itself.
Almost ready to join the big boys' club.
The windscreen is
cut from a ply template. It ends up fairly close to the steering wheel,
so an increased length of brass all-thread may be needed on the
steering column if small hands bump it.
One of the more high
stress jobs in this project is bending the drive axle around so that it
can be U-bolted to the wheel. A pipe bends it only just so far, and the
rest must be done by hammering...heavy hammering. A small sledge hammer
would be a good idea. Inevitably, one of the blows went into one of the
brake disc spokes and shattered it, so a small repair job is needed
there. But, eventually it is locked in and the drive train is in
action. The knock-offs are locked onto the wheel hubs by brass nipples,
and cotter pins hold their position behind washers.
But there is far worse in store than the drive axle. As I was unable to get any mild steel bolts of 7" for the font axles, I settled for stainless steel, which was available. Drilling holes through stainless steel bolts for the cotter pins was almost impossible, and it went through just about every drill bit I owned. Nevertheless, it was finally achieved after the best part of a day, putting the car into its final stages, before being boxed into an old refrigerator pack for wrapping and delivery. The tyres were washed and some general housekeeping was done just prior to packing, and the job was finished.
But there is far worse in store than the drive axle. As I was unable to get any mild steel bolts of 7" for the font axles, I settled for stainless steel, which was available. Drilling holes through stainless steel bolts for the cotter pins was almost impossible, and it went through just about every drill bit I owned. Nevertheless, it was finally achieved after the best part of a day, putting the car into its final stages, before being boxed into an old refrigerator pack for wrapping and delivery. The tyres were washed and some general housekeeping was done just prior to packing, and the job was finished.
There will be one more set of photos going up on this page showing the car being received by its new owner, and that will possibly answer the question as to whether it was worth all the effort.
The reception may have been more rapturous if he could reach the pedals!
In the meantime, to give me
something to do on the side while I am
building my next boat, I have ordered the Stevenson plans for their old
pedal biplane. That will keep me occupied while the marine epoxy
is drying.