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Scratch Building Tires - Diamond Tread Cutting


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Hello skilled modelers all -

 

I am lucky to have a table top mini-lathe and end mill combo.  With it I am able to turn small parts on the lathe for modelling.  It's a great way to make scratch built tires.  How many kits fail us with the tires?   Here is an example of what I did for a 1/18 scale P-38 build: 

 

027_zps8eitrto6.jpg

 

That tire (and its wheel parts) are made of acrylic whihc is quite machineable.  I can make block treads on tires, as shown in the picture.  The circumferential grooves are simply turned on the lathe with a very narrow tool.  And the radial grooves are just scribed (hard work). 

 

Here is my question.  Can anyone describe to me how one would cut WW2-style diamond treads instead of block treads?  I know it can be done, but I just cannot figure out how, outside of just plain brute force hand whittling, which will not give the needed accuracy plus would be soul-crushing difficult.

 

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I'm no machinist, but I think it is done with a threading tool attachment.....check YouTube...bet you can find something there

 

 

Knurling would be the only way with a lathe.

 

Unfortunately, these methods would only work on a cylindrical surface. I think multi-axis CNC is the only way that doesn't involve a ton of manual effort.

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CNC or resin-printing is the only way I can think of. Manually, making a couple hundred little diamonds and gluing them to a shaped tire!

Probably begging whatever person/company that has already printed and is producing 1/32nd tires to send CAD files to a 3D printer is the least amount of work... :hmmm:

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Guest Paul Budzik

You mean like these ...

 

http://paulbudzik.com/models/p51.pdf

 

http://paulbudzik.com/models/p47.pdf

 

Like I did back-in-the-day ... before 3D.  Of course, now it just can't be done ... impossible ... only way is 3D.

Pardon my sarcasm, but I get pretty tired hearing that there is no difference between something created by hand vs by a computer program that calculates everything for you.

 

They were actually easier than these ...

 

revell_p-38_lightning_1-32_001.jpg

 

Paul

Edited by Paul Budzik
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You mean like these ...

 

http://paulbudzik.com/models/p51.pdf

 

http://paulbudzik.com/models/p47.pdf

 

Like I did back-in-the-day ... before 3D.  Of course, now it just can't be done ... impossible ... only way is 3D.

Pardon my sarcasm, but I get pretty tired hearing that there is no difference between something created by hand vs by a computer program that calculates everything for you.

 

They were actually easier than these ...

 

 

 

Paul

 

You were/are a maniac, sir!! I'm in awe....

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You mean like these ...

 

http://paulbudzik.com/models/p51.pdf

 

http://paulbudzik.com/models/p47.pdf

 

Like I did back-in-the-day ... before 3D.  Of course, now it just can't be done ... impossible ... only way is 3D.

Pardon my sarcasm, but I get pretty tired hearing that there is no difference between something created by hand vs by a computer program that calculates everything for you.

 

They were actually easier than these ...

 

Paul

 

Paul, kudos on your P-38 and more so on the block tread tyres you created.

But they're totally conceivable with traditional modelmaking tools, careful measurement and patience.

 

Diamond treads with a helical offset, and winding up (ho ho) back at block one with precision and no overlap are a whole other ballgame.

Obviously, the tyre making companies managed it full-size 60 years ago without CADCAM, but that's not what we're talking about.

 

It can probably be done by hand - eventually, after all errors have been minimised one unit at a time by a 'traditional' modelmaker - but really?

Out in hobbyland?

C'mon...

Edited by Chek
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the problem here (at least on the ones I made) is that the tread may not be a groove cut out of the tyre, but rather a diamond stuck onto it

 

that is what I learned trying to make some for my 1/18 Spit and I still haven't sorted out getting them even..

 

when I was designing them I tried effectively scoring the grooves out if a bigger tyre and it didn't look right at all..

 

WIP254_zpso2ryqxym.jpg

 

..this was done in Rhino on a 90 day trial and lots of Youtube videos (and some help from Tim)

 

As for scratchbuilding, I had the same problem with some Sea Fury wheels and just couldn't figure out how it's done - maybe Harold can shed some light?

 

Peter

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As for scratchbuilding, I had the same problem with some Sea Fury wheels and just couldn't figure out how it's done - maybe Harold can shed some light?

 

Peter

 

Layout, layout, and more layout. Once you get the pattern penciled in I would use a razor saw to cut the grooves - with a tape mark on the saw to keep depth consistent. It's not a trivial problem to solve on CAD, either - lots of math!

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I have no mini lathe or milling machine. I wish I did.

I bought a bunch of kit wheels and tires from ebay years ago. They included 1/24, 1/25 car tires. Plus all the ones I tossed in my scrap piles over the years after I bought resin replacements.

If I need diamond treads, I try to find the actual tire sizes, convert it to 1/32 scale and hunt for one in my junk box that is close to actual in scale. I can adjust the width if needed then cast a copy in resin. If it has a diamond tread, or something that resembles it, I will use it as a guide. If not, I will use the two part epoxy and lay a thin layer all around the tire. I smooth it and blend it into the sidewalls as much as possible with a wet finger or cotton swab. Sometimes I will wait for a few hours for it to harden slightly then with the back of an x-acto blade I will very, very slowly and carefully roll a pattern starting on the "bottom", the flat I sanded into the resin tire. It takes several, or in some cases many tries before I get it close enough. Then I let it harden fully and sand around the tread to thin it down and give the pattern a sharper edge.  Most of the time I have clean up the grooves and sand some more. The one in the photo still needs the treads sanded.

 

 

IMG_2772_zpstiwwg8tj.jpg

IMG_2773_zpszbn9tajr.jpg

Edited by Harold
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Guest Paul Budzik

Chek:

 

"Diamond treads with a helical offset, and winding up (ho ho) back at block one with precision and no overlap are a whole other ballgame."

 

Well then, how the hell did I do it.  Maybe I didn't consider it inconceivable.  Maybe it's inconceivable because now modelers look for the easy approach.

But what happens is that when the problem solving skills fade away, then your options become limited, like fixing shape issues with kits.  What are you going to do, print a whole new model airplane.

 

You could just ***** about or fix it.

Take this for instance.

 

hqdefault.jpg?custom=true&w=196&h=110&st

 

https://www.youtube.com/watch?v=0g4E7E_UjIQ

 

 

Paul

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