Urethane Wheels Run off Cim Motor
 

A couple days ago, I posted a thread BaneBot Wheels Run off CIM Motor. Since then, I came across another thread where someone said the urethane wheels from mcmaster-carr work better. So I have the same question - how do you attach cims/miniCims to them?

Re: Urethane Wheels Run off Cim Motor
 

Machine a hub that press-fits into the wheel, bore out an 8mm hole in the center, and broach a 2mm keyway into the hole.

Re: Urethane Wheels Run off Cim Motor
 

Is that the easier way to do it? What about for teams with less machining capability?

Re: Urethane Wheels Run off Cim Motor
 

I don't know if we are talking about the same urethane wheels but the one commonly used is McMaster 2477k36 (seen on 1114, 973, 2056 and 254 at champs amongst many other teams). We used them on a suggestion from 973's Adam Heard and found them to be great.

So that McMaster number in 60A is what we and they used.
http://www.mcmaster.com/#catalog/119/1117/=o1d4kk

The hub really is the easiest way IMO. You only need a lathe.
We machined said hub to interface with 1/2" keyed shaft. The hub was just a piece of 6061 round stock turned to press fit into the wheels bore. I took a look at 1114s hubs and they knurled them to make the press fit better. We didn't have the resources to do so but were fine through all of champs.

Re: Urethane Wheels Run off Cim Motor
 

Use different wheels.

Re: Urethane Wheels Run off Cim Motor
 

If you want I think we have a left over hub or two we might be able to send you. PM me for details.

Re: Urethane Wheels Run off Cim Motor
 

You need some sort of hub to transfer torque to the rim of the wheel, and something to transfer torque from the motor to the hub. The first requires a lathe, and the second some sort of key, hex, or spline broach. If neither of these is doable, then this is not the wheel for you.

Re: Urethane Wheels Run off Cim Motor
 

You can use a trantorque style OD/ID expanding/clamping hub and just clamp onto ANY round shaft.

You may have to browse several brands to get the ID you desire. They do make bore adapters to get the ID correct.

This is actually how they are intended to be me mounted. The only downside is a hub is $20-60.

We chose to machine hubs just like the above teams, and were happy with that result. It's actually a pretty easy part for a lathe (especially if you use plastic as your OD tolerance is pretty loose as it'll deform when you press pretty easily). Our plastic hubs were like .015" large.

Very helpful. Thanks for your input.

Re: Urethane Wheels Run off Cim Motor
 

Does anybody know if any team had a working 3D printed hub, or any reason why a 3D printed hub would not work? (We have a friend with a printer.)

Re: Urethane Wheels Run off Cim Motor
 

I doubt a 3d printed hub would have comparable concentricity.

Re: Urethane Wheels Run off Cim Motor
 

My other question, why broach for a key instead of just broaching hex?

Re: Urethane Wheels Run off Cim Motor
 

If you guys don't have a lathe in-house, this might be a good opportunity to find some local machining sponsors! PM me if you want some one-on-one help finding them.

Good luck,
Akash

PS- I've taken the liberty of searching around your school for possible sponsors, and you've got quite a few solid options to look into. Shoot me a message if you'd like to check them out!

Re: Urethane Wheels Run off Cim Motor
 

A) Because the OP was asking how to interface these wheels directly with a CIM/Mini-CIM.
B) Because not everyone uses hex shaft

Re: Urethane Wheels Run off Cim Motor
 

Broaching hex would require a sleeve from AndyMark and a .5" broach. Considering that a 2mm keyway broach is much cheaper, if you don't use hex elsewhere, it's a lot easier to broach directly for the CIM output shaft.

Re: Urethane Wheels Run off Cim Motor
 

Has anyone attempted to use these 4" urethane wheels as drive wheels? At $30 each it would be an expensive setup, but they appear to be similar to Colsons but with a higher CoF.