[Brandon Holley]

Originally Posted by craigboez

I'm especially interested in more details on getting a dual-hardness roller. Since a hard roller doesn't provide much traction and a soft roller is too compliant, the ideal setup is a hard core and soft outer surface for the rollers. From what I read team 357 uses two different casting materials and from their pictures I can see team 2865 just used a hard PVC-looking tube as their core. Anyone care to comment on how to best accomplish this?

I'm also interested in making the inner surface as slippery as possible, to act as a bearing against the axle. Does anyone have experience either a) machining Nylatron or similar material (something filled with molybdenum disulphide), or b) buying Moly powder and adding it to a urethane casting?

It's funny seeing your thought process throughout this thread. It's the exact same thought process I had when I was working on my little wheel. It all depends on how extreme you want to go on reducing that friction. Using Teflon or Delrin will be effective, but the urethane will not adhere to it, so doing some kind of insert mold is out. I looked at even purchasing tiny ball bearings to press into the rollers.

Ethers point of friction along the face should also be noted. I imagine this friction would be the harder one to solve elegantly.

Good luck!

-Brando