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I'm planning on building a 4WD buggy from scratch, I think I have most of what I need to do it. But I'm not an engineer by background.

I want the car to be as strong as a modern race buggy, the problem I currently have is materials selection. The easy bits:
- Machined parts that are not in the drivetrain will be 7075 T6 aluminium.
- Gears will be made from PEEK (maybe moving to steel later if needed - but I would have to get someone else to do this as I don't have something that could hob straight cut steel bevel gears)
- Towers will be made from sheet carbon fibre.
- Covers (like dust and stone guards) will be poly-carbonate.

The problem I've got is choosing what grade of steel should be used for things like diff outdrives, driveshafts, and axles - there seems to be a large number of different grades available, all I know is that it needs to be strong, machinable, and probably needs a bit of flex to prevent snapping/shearing, does anyone know the grades use on modern cars? Or any thoughts on grades to try? I'm happy to experiment with a few different grades - but it would be nice to be able to narrow my testing to a small number of types.

For the platic moulded parts I think I'm going to have to experiment with a lot of different blends (PC-ABS might be good) but does anyone have any experience in plastic injection moulding and could recommend a strong mouldable plastic suitable for use in suspension arms? And what kind of % glass (or other) fillers should be used?

I fully expect this project to take a lot time with a lot of trial and error - but hopefully some members can help reduce the amount of materials I should even bother looking at considerably!

Many thanks

Most steel part will be fine if you use something like O1 or W1, annealed. If something needs to be wear resistant or hardened, like an out drive, both of those grades can be hardened and tempered.

It's a bit of science and magic though, so i'd consider finding a model that exists that you can lift parts from, like a full diff. It's much easier, faster and often better than prototyping parts. Especially gears and drivetrain.

Don't discount g10 for parts, and I usually use nylon or delrin for parts I make like arms, bulkheads, etc.

jwscab wrote: ↑Sat Jun 29, 2024 12:42 pm Most steel part will be fine if you use something like O1 or W1, annealed. If something needs to be wear resistant or hardened, like an out drive, both of those grades can be hardened and tempered.

It's a bit of science and magic though, so i'd consider finding a model that exists that you can lift parts from, like a full diff. It's much easier, faster and often better than prototyping parts. Especially gears and drivetrain.

Don't discount g10 for parts, and I usually use nylon or delrin for parts I make like arms, bulkheads, etc.

Have thought a lot about lifting some parts from another model, but ideally I'd like to produce a batch of these cars for sale if it goes well and I don't really want to be tied to the availability of someone else's bits! I've used some Tamiya steel diff internals from the TA06/M07/TRF201 on my mockup and tracking the parts and availability it seams very unpredictable!

Thanks

Just throwing it out there but if you were to use a diff for example from an existing model, and you decide to roll with it, you could always reverse engineer it and produce them if they become hard to source. Also could lead to people buying the parts from you when they also can't get them easily from said manufacturer. Win win.

Definitely pick a different manufacturer rather than Tamiya. They tend to release, let the market dry, and then.... maybe re-release.
They aren't super reliable for spare parts.