Urethane Wheels Run off Cim Motor

[xForceDee]

A couple days ago, I posted a thread BaneBot Wheels Run off CIM Motor (http://www.chiefdelphi.com/forums/showthread.php?t=118366). Since then, I came across another thread where someone said the urethane wheels from mcmaster-carr (http://www.mcmaster.com/#standard-polyurethane-wheels/=o1cwh9) work better. So I have the same question - how do you attach cims/miniCims to them?

[T^2]

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.

[Walter Deitzler]

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.

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

[HammadB]

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.

http://i42.tinypic.com/51onpf.jpg

[Gregor]

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

Use different wheels.

[HammadB]

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

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

[T^2]

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

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.

[AdamHeard]

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.

Use different wheels.

Very helpful. Thanks for your input.

[Walter Deitzler]

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.)

[AdamHeard]

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.)

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

[Walter Deitzler]

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.

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

[Akash Rastogi]

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

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!

[Lil' Lavery]

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

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

[T^2]

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

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.

[craigboez]

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.

[T^2]

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.

They stretch a lot. You might have to mold your own urethane tread around an aluminum or plastic rim that doesn't buckle. (I think 118 does this? Not sure.)

[DampRobot]

They stretch a lot. You might have to mold your own urethane tread around an aluminum or plastic rim that doesn't buckle. (I think 118 does this? Not sure.)

Yep. They actually do a custom wheel mold too.

Just tread a wheel or buy one. Its much easier, and the wheels that are out there are already great solutions for drivetrains.

[whophil]

Colson makes a lot of wheels in addition to the "Performa" line sold cheaply at RobotMarketplace.

Colson has a line of polyurethane-tread wheels molded over aluminum, polyolefin, and cast iron cores. You can see the specs for these wheels here:

http://www.colsoncaster.com/products/wheels/polyurethane/default.aspx

I found some 6" polyurethane on polyolefin wheels on eBay for about $10 apiece.

I can't comment on the construction and concentricity of these wheels as I haven't received them yet, but if you ask me again in a few weeks I should have an answer for you.

[Chris is me]

There's a lot more that goes into whether or not a wheel is good for frisbee shooting than "does it use polyurethane"? Polyurethane varies widely in durometer (hardness), thickness, etc. The blue McMaster polyurethane wheels used by many teams this year have a very thick polyurethane layer (seemingly over an inch of polyurethane) bonded to a metal hub / core. Many wheels (Colsons I believe) have a much thinner polyurethane tread molded over a plastic core. Your mileage may vary.

While Gregor's suggestion was somewhat snide, if you do not have the machining capability to make a simple press-fit hub, these wheels really aren't the best option for your team. Investing in several of the Blue Banebots rubber "poverty" wheels would probably be more beneficial. Do note that despite being the same durometer, the Banebots wheels have drastically different wear characteristics than the McMaster wheels, and they need to be changed out over time.

[AdamHeard]

While Gregor's suggestion was somewhat snide, if you do not have the machining capability to make a simple press-fit hub, these wheels really aren't the best option for your team. Investing in several of the Blue Banebots rubber "poverty" wheels would probably be more beneficial. Do note that despite being the same durometer, the Banebots wheels have drastically different wear characteristics than the McMaster wheels, and they need to be changed out over time.

Unless price is a huge driving factor (and it being so late in season, concerns over wear become smaller) the mcmaster urethane wheels are mounted incredibly easy with the style hub I recommended.

If you're trying to be cheap and fast, can't argue with the poverty wheels for a single offseason event if you're not going to practice much going into it.

[Akash Rastogi]

Hey, since when did we start calling them poverty wheels? :p

Relevant note, we've found a few machining sponsors in Walter's (LedLove96) area. We'll have them up and running with new resources soon :)

[AdamHeard]

Hey, since when did we start calling them poverty wheels? :p

Relevant note, we've found a few machining sponsors in Walter's area. We'll have them up and running with new resources soon :)

I was hassling 330 and 1717 at the LA regional for their poverty wheels, I guess it stuck after that.

Luckily they both switched to respectable wheels after that event.

[Walter Deitzler]

Hey, since when did we start calling them poverty wheels? :p

Relevant note, we've found a few machining sponsors in Walter's (LedLove96) area. We'll have them up and running with new resources soon :)

It is true. while we are going to be using the "poverty wheels" for club fair and a demo coming up, we hope to have hooked up with a sponsor and have some hubs machined by the Cow Town Throw Down. While a single off-season event will not be worth the wheels, the sponsorship gained just might,

[AllenGregoryIV]

I was hassling 330 and 1717 at the LA regional for their poverty wheels, I guess it stuck after that.

Luckily they both switched to respectable wheels after that event.

Seeing as I'm on the team that first made these wheels popular, I will say that there are better options. However, giving them a name like this may stop a lot of teams from using them and potentially stopping them from making themselves better. Let's not let this get too far out of hand. Also, seeing as Banebots have been a long time sponsor of FIRST I doubt they want any of there products referred to like this. I completely get the joke and would probably make it myself but once it gets out in to the community in can have many negative effects.

[AdamHeard]

Seeing as I'm on the team that first made these wheels popular, I will say that there are better options. However, giving them a name like this may stop a lot of teams from using them and potentially stopping them from making themselves better. Let's not let this get too far out of hand. Also, seeing as Banebots have been a long time sponsor of FIRST I doubt they want any of there products referred to like this. I completely get the joke and would probably make it myself but once it gets out in to the community in can have many negative effects.

I can agree with all points made except their reputation.

Sponsoring FIRST doesn't mean their poor product and quality control should just be ignored.