Quote:
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?
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Why not just cast the bore larger, and use a Teflon tube insert?
Also, be aware that the bore friction is not the only concern. There are substantial axial loads on a mecanum roller, so you have to address the end-loading friction. A stack of thin Teflon washers at each end might do the trick. They could also serve the dual purpose as shims to reduce axial free play (which affects mecanum performance).