Hello, team 4322 is in need of some help getting tread cut and drilled to properly fit the WCP Swerve X wheels.
Every time we try to make tread it becomes a problem because typically at least one of the holes drilled in the tread is slightly off making it nearly impossible to get the bolt in without stripping or cross threading the wheel. We have tried to make our own tread drill jig out of some aluminum extrusion and use this one by team 2811 but are still having issues. We have found that the tread we are using has some slight variance in width causing some of the strips of tread to move in our jigs and cause further misalignment.
Another issue that we are having with the tread is how close the holes are to the edge of the tread/wheel causing some of the bolts to rip out the side of the tread while driving. It appears that the tread from thrifty bot is the 3 inch wide tread from McMaster cut in half, so it is inherently slightly smaller than 1.5 inches wide making the holes closer to the edge. We are considering drilling our own holes spaced closer to the center of the wheel. If we do make our own holes we are not sure if it would be best to tap them (and risk stripping them out again) or to use clearance holes with nuts on the inside, or to rivet the tread to the wheel. We are also considering buying 4 inch wide tread from McMaster to ensure the tread is a minimum of 1.5 inches wide but are not sure how to best resaw the tread in a straight line.
If anyone has found the magic way to make perfect tread every time please let us know.
After working on this for a season, we managed to get our yield up to about 70%-80%. Our biggest trick was putting a leather working hole punch in a drill press and using a 3d printed guide that was experimentally derived to be correct.
We also found that the specific tread.
Changes the spacing on the holes
We had a hard enough time that we are looking into alternate solutions for wheels
I forgot to add that the tread template only works for blue nitrile tread since black neoprene stretches differently. I will go add that right now. Sorry for the issues you had with my design.
Edit: The only recommendation I can give is to drill the tread manually based on the wheel itself and measure it, then, design a template based on those dimensions.
A couple of thoughts: you can lace the holes together with something to pull tension, and then clamp it on with a worm gear hose clamp (a big one). Then add screws. Or, just go straight to the clamp.
I experimented with using safety wire lacing on the wheels for my clone of Nick Cousin’s winter swerve. Easy to get plenty of tension, not sure if it will transmit enough tourque. Its only driven a couple of feet, so no real results yet…
This test was laced with Copper wire; I also did them with stainless steel wire. Its easier to lace them inside out and flip. I had two tapered hubs that pulled the whole thing tight.
You can -just- see the safety wire:
It can be helpful to use longer screws. Keep the tread close to the head of the screw, so that the end you are trying to thread in is not under tension. The geometry helps as well, but some of it is just being able to see what the threads and hole are doing. You can attach one end with short screws, and then wrap all the way around and use longer screws only on the other end. At that point, you should be able to align the holes and use short screws for everything in-between.
