Centurion Mk III Scratch build

[AlwynTurner]

First completed Centurion wheel with the correct centre cap



Lots more printing to do!

Alwyn

[Pak36]

Looking sweet

I am curious how you handle the actual suspension part of hte suspension units. I can see you have a mount bolted to the swing arms and a thick core with the spring over it....but what happens on the other end?

I have tried 3D printing shock bodies before, and struggled to make anything strong enough to be of use. Either I printed it horizontal to get strength...and it looked horrid...or vertical, where I got a good round shape to match the spring...and it would snap along a layer join under load.

Really fascinated how you have approached this, as these look really functional and up to the job.

Mine didn't

[AlwynTurner]

I've dismounted the suspension and put it on the outside of the frame so you can see. Basically it's down to how you design the parts - making them 'meaty' enough, and then very much how you print them. printed parts do not take kindly to stresses placed along the deposition layer, so I always try and print so the stresses are taken against the deposition layer (if that makes sense. A case in point is the spring holder which is printed vertically. All the stress on this piece is passed through the layers to the mounting and there is no sideways stress to fracture the print.



You can see the deposition layers on the swing arms which are very strong. On these parts I use a very thick wall (1.5mm) and a 50% infill, and they seem to work just fine.

Hope that helps, if you have further queries just post them and I'll try and answer.

Alwyn

[Pak36]

Massive thanks

Didn't expect you to dismantle the whole thing!

I have learnt a few lessons about deposition layers and stress fractures, all of which I have learnt the hard way!

Your approach to the spring is a far simpler one than I was trying, and to be honest...I think I was overthinking what I was making. Seeing how you have done it avoids all the issues I was having trying to have a rod sliding in the middle like a full on suspension unit, where you have just the plugs at either end sitting in the spring. You have fewer parts, and stronger pieces....whereas I was making a micro suspension shock unit which was just not ever going to be strong enough. It looked good...but what's the use of that when it snaps just being put together, let alone survive use.

Your approach is simple, and strong...and once the thing is put together, all the extra bits I was messiong with are hidden. You have a beautifuilly simple HVSS layout which I am going to shamefully borrow design details from!

This has been a massive help and I am really grateful you took the time to show me the detail. Thanks!

[AlwynTurner]

Glad I was able to help. I have always believed in the KISS principle (keep it simple stupid!) and I have found from sad experiences that quite often strong is better than elegant, especially where you can't see the working parts!

I'm very happy for anyone to borrow any design bits that are useful and the reason for publishing the designs is to help everyone with the cad design experience (not that my designs are anything to write home about - there are usually five better ways of doing things than the way I do them!)

Alwyn

[Ad Lav]

Great work so far - I bet it’s a lot cheaper than Ludwigs.

[AlwynTurner]

It sure is, but a lot of tedious printing! Still, no pain no gain.

Alwyn

[AlwynTurner]

Printed the first sprocket, it's substantially different in design to the Chieftain but the sprocket teeth/spacing are the same




Alwyn

[midlife306]

Looks brill Alwyn, can’t wait to get back & hit print


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[c.rainford73]

Looks like you are well on your way to another masterpiece Mr Alwyn. From the suspension to the sprockets simply brilliant!