Scratch build Nitro tethered race car, second try!

[Roog]

So that's about 270mm, a little bigger than typical 1/10 touring car body scale. Just wondering what type of body might be out there for that. Might be something to get made custom.

I think the big issue is that typical rc cars have wide chassis to accommodate all of the gear, limiting the car body’s to wide bodied cars with a smattering of modern f1 / Indianapolis like cars, also o don’t suppose there is much call for vintage race cars, sadly.

Back at the shed, I have been making the axles. After facing off the ends and centre drilling so that I can support the end from the tailstock using a live centre, a pointy metal cone running in ball races. Then machine a section down from 10mm to 8mm on which to mount the wheels.

Next I need to cut a M8 male thread on the ends of each of the axles, this gives me an opportunity to use my sliding tailstock die holder, snappy title huh? The purpose is to hold the threading die square to the work piece allowing pressure to be applied to the die while the work is turned to cut the thread saving lots of wobbly hand wrangling of the old die holder. I’m not sure that I’ve figured out how to use it properly but it worked OK.

 

[Roog]

Next to cut the key ways to engage with the drive wheels. Because these are cut into an 8mm shaft I have chosen a narrow key 2.5mm wide and 6mm long.

This gave me a chance to use my collet block which is used to hold cylindrical things firmly and to orientate it squarely. To make the key I am using 6mm diameter silver steel bar to make the tiny oval profile keys.

So to make the keys, clamp the bar firmly in the collet block and machine the top side down by 1.75 mm, then flip it over 180 degrees and machine the other side to the same depth, leaving a 6mm x 2.5mm strip from which to cut a couple of keys to engage the rear wheels. Because the collet is mounted in a precisely machined square block the work piece, once clamped can be rotated in 90 degree steps allowing faces to be machined accurately at right angles without having to recalibrate the cut because the block mounts the work on its centre of rotation.

I now realise that I should have taken more photographs

 

[Roog]

And here’s a photo of the chassis complete with axles and engine

 

[Roog]

And so to wheels, I am trying an experiment. Because I don’t anticipate this car being very quick I am going to try in-line roller skate wheels, hey if the don’t work I can revert to my own design, but if they are adequate then I can make 4 wheels in less than a day vs 1 and a half days per wheel. Plus tyres plus grinding to finished diameter.

Starting with the hubs, the inner one is mild steel because it has to engage the key, the outer parts can be aluminium to save some weight.

Face off, centre drill and drill hole to one size less than the final size which will be reamed out to 8mm. Then turn down to size,the wheels have a recess which accepts 22mm diameter bearings, so 22mm it is, the hub parts are each 7mm thick, the size of the bearings which would normally be used.

Then part off to length, in this case 7mm

Same for the aluminium parts, same just shinier .

Then cut a slot for the key way with my small milling bit, just ‘drill’ down from the top and them mill out the the centre to create the slot.

And here are the wheels assembled, the front ones have skate bearings as nature intended.

And here they are loose fitted to the car chassis

 

[Roog]

I’ve printed out the few frames I have for my car body and stick then to 3mm plywood, I would have preferred more, but I’m going to set them up on a keel and see how they look.

As I don’t have any very thin plywood (1/64” thick is really pliable) I might test out the lines across the frames using thin card to see how it looks.

 

[Roog]

I have planked the frame, just like the old days of making model boat hulls albeit quite a bit more rushed and rough!
But hey it just needs more sanding and resin and sanding etc. It needs a rear end which will be solid blocks carved and a front nose which might be fashioned from aluminum. Then I have to decide what to do with it. Make a mold from it to cast a GRP body or plate over it with thin aluminum panels or tin plate. I recon the top half will be a bugger to release from the mold.

Does anyone know if you can solder thin aluminum sheets together? say 0.7 to 1mm thick

 

[Roog]

 

[Doom!]

You did that pretty quick, gonna look good!

 

[CertifiedMike]

Kyosho ran 270mm. Not sure of all the bodies they made for that W.B.
Team Blue Groove would be a good place to ask.
They seem pretty into vintage and Kyosho. They have TONS of bodies.
Sebula on ebay and https://landlmodels.co.uk has a bunch of cool vintage too.
Maybe they have or know how to get one.

 

[CertifiedMike]

The body you are building doesn't really look like it needs any "help" imo.
I think it looks real good actually!

 

[Roog]

Kyosho ran 270mm. Not sure of all the bodies they made for that W.B.
Team Blue Groove would be a good place to ask.
They seem pretty into vintage and Kyosho. They have TONS of bodies.
Sebula on ebay and https://landlmodels.co.uk has a bunch of cool vintage too.
Maybe they have or know how to get one.

Thanks @CertifiedMike i will check these out

 

[Roog]

Oh bugger, like the true idiot I am, I've managed to slash my left hand with a scalpel, I'm not going to post pictures.
Nothing major and its not the end of the world so its bandaged up but I'm not really in a position to do much right now I need it to heal for a full on site visit next week. :0(

Just angry with myself for not taking proper care, again.

 

[Doom!]

Oh bugger, like the true idiot I am, I've managed to slash my left hand with a scalpel, I'm not going to post pictures.
Nothing major and its not the end of the world so its bandaged up but I'm not really in a position to do much right now I need it to heal for a full on site visit next week. :0(

Just angry with myself for not taking proper care, again.

Take care, we aren't going anywhere. Been there done that, felt pretty dumb.

 

[tudordewolf]

Next to cut the key ways to engage with the drive wheels. Because these are cut into an 8mm shaft I have chosen a narrow key 2.5mm wide and 6mm long.

View attachment 207097

This gave me a chance to use my collet block which is used to hold cylindrical things firmly and to orientate it squarely. To make the key I am using 6mm diameter silver steel bar to make the tiny oval profile keys.

So to make the keys, clamp the bar firmly in the collet block and machine the top side down by 1.75 mm, then flip it over 180 degrees and machine the other side to the same depth, leaving a 6mm x 2.5mm strip from which to cut a couple of keys to engage the rear wheels. Because the collet is mounted in a precisely machined square block the work piece, once clamped can be rotated in 90 degree steps allowing faces to be machined accurately at right angles without having to recalibrate the cut because the block mounts the work on its centre of rotation.

View attachment 207098

I now realise that I should have taken more photographs

I'm impressed by that effort to add a woodruff key, I'm thinking I may eventually have to do that for one of my engines that just uses a "D-washer" and has been known to split it - did you have to take any special care to machine the hardened steel of the crankshaft?

 

[Roog]

I'm impressed by that effort to add a woodruff key, I'm thinking I may eventually have to do that for one of my engines that just uses a "D-washer" and has been known to split it - did you have to take any special care to machine the hardened steel of the crankshaft?

I think the reason why I perused the woodruff key is because the crown gear had the slot ready cut in it so I thought I’d give it a go, it was quite satisfying to do although I am concerned that the pulsing of torque from the engine might damage it quite quickly.

The drive shaft is silver steel and seemed reasonably easy to machine the slot for the key, I attached the flywheel to engine crankshaft by a tapered collet, I’m quite proud of that, not least because I’ve tried matching tappers before and messed it up properly. So I managed to avoid machining the crankshaft which as you say is quite hard.

 

[CertifiedMike]

I have been slicing myself up with all sort of metal for decades now.
You'll look back on this post one day, years from now and look at your hands, scars and won't remember which scratch this was!
Heal well! We'll wait!

 

[Roog]

Cheers @CertifiedMike I've been pretty good at avoiding slicing accidents for quite a while, although I have had to drive myself to the Accident and emergency department a couple of times in my life with one hand bandaged and my wife complaining not to get blood on the car!

 

[CertifiedMike]

I understand! I get yelled at for leaking blood too!
Almost as if I'd decided cutting myself WAS the intended job and I should have planned it better!

 

[Roog]

Managed to stick some small blocks of soft wood to the rear.

 

[Roog]

Carving and sanding starts once the glue sets hard and I pluck up the courage to pick up a knife again, maybe a session on the sander is required and dremel. Not so much precision involved in this work.

If I am to use this to make a mould I am going to have to resort to filler.