Attaching Plaction Tread to Delrin Cylinders

So, for one of our off-season projects our team is manufacturing custom traction wheels out of delrin and plaction tread. I had heard that the best/easiest way to do this is imply to attach the tread to the delrin via. wood screws, but I’d like to get some additional input before we actually attempt this as it’s not something I’ve done before.

Could anyone with experience doing something like this offer some advice on how best to do it?

I would suggest tapping some holes in the delrin hub and fastening the tread with machine screws, like button head phillips or something that you can easily take in and out with a power drill. This is what we did this year with our 3d printed ABS wheels. Beats rivets when it comes to maintenance.

Thanks a bunch for the advice. So, you’d recommend using a tap rather than just a pilot hole and a self-tapping screw?

Honestly, either would work just fine. You’ll change thread a few times per season at most depending on what material you get.

Agreed, either is fine, but by tapping the threads you get better threads and holding power, and gain re-usability well in excess of what self-tapping screws can provide. Plus machine screws have a wider variety of head profile available.

Tapping in delrin is easy.

What Don and Chris both said. Don’s post also reminded me of my love for Delrin, it’s so nice to work with.

Back on topic though, should you ever see or feel the need, you can also look into installing threaded inserts into the wheel, either a knurled press in type insert or a riv-nut should work pretty well. Only way I can see you having issues with threading right into the delrin wheel is if you have to change tread frequently and use a drill. If you don’t start the threads by had (always start the threads by had) you could risk damaging/destroying the treads.

We have been using tiny wood screws on UHMW wheels for many years and have never had any issues. We also did this on Delrin rollers last year, makes replacing the tread very easy.

When we replace the tread we attach it again in a different spot and never have to worry about lining up with any existing holes. Works great.

We actually make Aluminum wheel “rims” and an outer disk of UHMW just so we can easily replace the tread using small wood screws. All you need is about 1/4" of material and maybe 6-8 screws per wheel.

Reading through the posts, I was wondering what you guys would suggest to use for a head type. I was thinking a hex head tek screw wouldn’t be ideal because you’d have the bump sticking out from your wheel. This makes me think counter-sunk screws would be the best. However, since counter-sinking plaction tread would be pretty hard, would just plowing the screw into the tread until it’s level do? It just seems like head type could be an issue.

We’ve always done it with short wood screws when we couldn’t rivet; we’ve never needed to change them enough times over a robot’s service life that it was necessary to be fancier.

We use small phillips screws or flat head wood screws. No need to counter sink. Once you screw it in the head of the screw will hide under the rubber pretty nicely.

Agreed. It doesn’t need to be flush, just lower than the rubber. Try a flat head, or maybe a Truss or Flat Filister.

You should try low profile drilling screws

Mcmaster 94090A100 or 92715A320

They are almost like a pop rivet but are removable