Model car. Mercerdes Silver Arrow .. getting there!

[stef]

This is my next project.
birthday present for a 2 year old boy !

I intend to make it around 40cm long, out of a few pieces of laminated wood. hopefully 2 lighter tone (or darker) to emulate racing stripes on the whole length of the car.. the front air intake will be routed before any shaping takes place.
i might make the wheels out of wood or buy them already made.
I'd like the whole thing to be steereable, and roll on ball bearings.


I am deep into planning, at the moment. what do i cut first and so on.
one thing i am not sure about is how to get the profile right.
As you can see on the plan, i have 4 section cuts available. but those dont really fall into any "natural" section cuts i could have in the build.
so how do i make sure my profile is right ? should i cut the half sections out of MDF, and just shape the block of wood until the profile is met ?

 

[Shultzy]

My first thoughts would be to decide if its going to be painted or just plain wood. If painted the wheels can be bought, if not the wheels will look much better if made in wood.

Scaling down to 400mm may make some of the parts too small to be strong enough.

Make it hollow as this would make the steering easier to fit.

Use a profile tool to check the curves of the body as you shape it.

 

[stef]

My first thoughts would be to decide if its going to be painted or just plain wood. If painted the wheels can be bought, if not the wheels will look much better if made in wood.

Scaling down to 400mm may make some of the parts too small to be strong enough.

Make it hollow as this would make the steering easier to fit.

Use a profile tool to check the curves of the body as you shape it.

it will be wood..shellaced.
of course ! i didnt think about using a profile gauge. i have one laying about !

 

[Night Train]

Work out the wheel size first. Most vehicle model makers who don't make their own scale wheels will get whatever wheels they can find that are suitable and then take the scale as a ratio of wheel diameter.

Anyway, That is how I do it with Lego Technic.

Sort out your steering mechanism to fit the scale of the wheels and have the axles organised for all the fixed and movable mounts. You may want to fit the axles onto a 'floor pan' so that it is all properly located with or without any suspension.

The 'floorpan' can be laminated into the body at the correct height.

You should be able to then laminate up in horizontal slices cut to be close to the inside and outside profiles.
Make up the bottom half first, with the 'floor pan' and shape the inside. Then make the top half and shape the inside then glue together before shaping the outside.

That will give you a solid structure with the steering and axle mounting all in the correct locations.

Also, for a two year old you should make the steering and axles fairly substantial to make it strong enough even if it is a long way out of scale.

 

[stef]

Work out the wheel size first. Most vehicle model makers who don't make their own scale wheels will get whatever wheels they can find that are suitable and then take the scale as a ratio of wheel diameter.

Anyway, That is how I do it with Lego Technic.

Sort out your steering mechanism to fit the scale of the wheels and have the axles organised for all the fixed and movable mounts. You may want to fit the axles onto a 'floor pan' so that it is all properly located with or without any suspension.

The 'floorpan' can be laminated into the body at the correct height.

You should be able to then laminate up in horizontal slices cut to be close to the inside and outside profiles.
Make up the bottom half first, with the 'floor pan' and shape the inside. Then make the top half and shape the inside then glue together before shaping the outside.

That will give you a solid structure with the steering and axle mounting all in the correct locations.

Also, for a two year old you should make the steering and axles fairly substantial to make it strong enough even if it is a long way out of scale.

That's very interesting, and not really what i was going to do:
in your approach, you go for horizontal lamination (if i read correctly), a bit like a stack of slices.
This is not suitable for me, as i plan to have light wood color for racing stripes, so i need vertical slices... something like this:

your approach is still interesting though. There are three ways to laminate the slices here. yours (bottom to top of the car), mine (left to right) and the classic boat hull one i used before (front to rear of the boat)

I guess following on early advice, i will go for home made wheels.. in oak. so size is not an issue.

so here is my plan as it stands today:
1- cut an odd number of slices to make the width of the car (say 7 slices, 15mm thick). 2 of those will be lighter tones, for the stripes.

2-mark the slices to identify in which order they will be laminated.

3-take each individual slice, and mark the outline of the car, as well as the outline of the cavities (cockpit, steering location, rear axle housing). . cutout the inner cavities. at this stage, each slice may be different. the inner slices will show the inside cutouts, whereas the outer slices will be solid. The inner 3 or 5 slices will show the inside floor pan , as well as the cavities through the floor, for accessing the stuff. on the two outer slices, mark out the position of the wheel axles.
on the inner slice, drill out the tunnel for the steering column

If possible, at this stage, also cut out the upper outline of paired slices..this way, you will end up with a lego type lamination, but at least, it will be symetrical. but only at the top of the car(slices). the lower edge of the slices will be used to make sure the lamination is in line. the front and rear edges should also be left untouched.


4- glue up the slices
5- since the front is still square, route the air intake at the front.
6-drill the wheel axles, making sure you are square. (drill in two halves)
7- shape the car. belt sander/rasps/files etc..and of course, using the profile gauge.

this is where i am now, as far as my plan goes.
at this point, i should have a w165 shaped hull, with inner cavities and tunnels for steering racks.

yesterday, i worked out the mecanics of the steering rack. i will need to braze a few bits of brass.
now i still need to think some more to work out if the steering rack can be fixed inside the hull, in the shape it's in.
i also need to work out the suspension, and the ball bearing wheels...how do i make sure the bb wont come out of the wheels ?

 

[CWatters]

One option would be to do it as a planked construction.... Make formers/frames to suit the cross section. Cut in half horizontally and fix upright to a board. Then plank the top with strips of wood. These could be different colour to produce the racing stripes. Once you have done the top remove from the board and fix the bottom half of the formers in place and and plank the underside. Sand round when dry. Extend the planks beyond the front former. Use a block for the very back end. Choice of glue will be important as would cutting the planks accurately.

This drawing shows how to do set up to do a model yacht but I've done it the same way on model planes with round cross sections...

 

[CWatters]

If you were going to paint it you could carve and sand the shape out of a block of polystyrene foam, coat it with glassfibre mat and tissue using epoxy resin (not polyester). Fill any defects with filler. Then disolve out the foam using petol... but that's not woodworking.

 

[stef]

One option would be to do it as a planked construction.... Make formers/frames to suit the cross section. Cut in half horizontally and fix upright to a board. Then plank the top with strips of wood. These could be different colour to produce the racing stripes. Once you have done the top remove from the board and fix the bottom half of the formers in place and and plank the underside. Sand round when dry. Extend the planks beyond the front former. Use a block for the very back end. Choice of glue will be important as would cutting the planks accurately.

This drawing shows how to do set up to do a model yacht but I've done it the same way on model planes with round cross sections...

Like the one i made previously ?
https://www.ukworkshop.co.uk/forums/view ... highlight=

i thought about this solution for at least 7.5 seconds.
imagine what a 2 year old boy will do to your matchstick eiffel tower...

 

[Night Train]

That's very interesting, and not really what i was going to do:
in your approach, you go for horizontal lamination (if i read correctly), a bit like a stack of slices.
This is not suitable for me, as i plan to have light wood color for racing stripes, so i need vertical slices... something like this:

your approach is still interesting though. There are three ways to laminate the slices here. yours (bottom to top of the car), mine (left to right) and the classic boat hull one i used before (front to rear of the boat)

You could mix and match.
Have a floor pan that is then set into the side to side laminations. Have a set of laminations for above the floor pan and a set below it to match to get teh racing strips. Just make sure that the floor pan is hoised in so that it doesn't show through the front and rear stripes.

 

[stef]

it's a good idea.. but what would be the advantage of doing this ?
i cant really see any clear advantage of a floor pan. (but i am open to the idea !)
on the other hand, i have completed the drawings for the dampers, and steering. i also concluded that the setup i chose can be mounted onto the car, with the current assembly plan i worked out.


i also started to play around with brass.
cutting, drilling is easy enough. first attempt at bending ended with a broken piece of brass (i am working with 100mmx2.5mm bars).
i plan to try brazing two pieces together tonight. and this may be the key to making brackets (if i cannot bend the brass).

The only thing i am stuck with, right now, is the ball bearing and the wheels.
I know how i want the bearing in the wheel, and how i goes onto the axle, but i dont know (not happy with) how the bearing is attached to the wheel.

so far, the bearing is housed into the wheel, and the only solution i have to keep it secure is to have some sort of washer covering the bearing, overhanging on the bearing outer ring and the wood, and screwed into the wood.
pulling the wheel will result in all the force beign placed on the holding screws. and i feel they will fail.

 

[Night Train]

I tend to use a floor pan as I work in the same way as a real vehicle chassis. All the mechanical parts would be fixed to this to ensure locational accuracy and then it is clothed in a body.

Probably no great advantage, just the way I would tend to work.

 

[stef]

yes, i definitely see how it would make sence on some (most) cars.
on this one though, the wheel axles come out of the shell, rather than going under wheel arches. so this means drilling the axles hole out, which means the wheel axles cant be attached to a floorpan from which the shell could be lifted.

 

[stef]

First brass parts done.
Those are steering and front axle components.

 

[stef]

good progress on this in the last couple of days.
I prepared the planks. made sure i had the width right, and an odd number of planks.
Then i drew the outline of the car on each pieces, as well as the inside cavities.
I cut the waste with a jigsaw.
tried out the steering, before glueing the planks together.
I also started turning the wheels.
I still need to refine the shape, but it is getting there !

I decided to make the wheels in two halves. this way, i can insert the ball bearing, and it will hopefully not fall off !

 

[stef]

Today's work..
some more shaping. i used the belt sander, before some more shaping using chisels.

 

[Boz62]

Well done, good progress. I see what you mean about needing to be kiddie-proof. This looks like it should do the job well, and is already looking nice

Boz

 

[stef]

tonights progress: