mecanum wheel defects? (help)

[John G]

Our team has been having trouble getting our mecanums wheels to function properly.
When we tighten the bolts and lock nuts so that the bolt is in the lock part for the rollers, they bind up. When we tighten them so they are not in the lock part of the nut, but still 3/4 of the way in the nut, some of them seem to loosen up and the rollers fall out. Any help for us?

[EricH]

Flip the lock nut around so that the lock part is towards the bolt. That should do the trick.

Or get longer bolts.

[Jon Stratis]

My vote is for longer bolts - flipping the nut around is going to be rather difficult, as you won't have threads to help push you into the nylon lock.

[scottydoh]

Are they the AndyMark Wheels? And what size are they?

[John G]

Thanks. As of now, we have the nuts in backwards, but we cannot find longer bolts that are the correct size in any store . . . . and they are the AM 6" mecanum wheels.

[sanddrag]

For bolts, I'd recommend McMaster Carr

[ayeckley]

Originally Posted by sanddrag

For bolts, I'd recommend McMaster Carr

I can confirm that McMaster-Carr does carry the appropriate longer bolts. Sorry, don't have the P/N handy. We found that adding 5mm in length was enough to allow us to back off on the torque a little to the point that we've got non-binding rollers, without causing any interference issues due to the longer length. The picture on the A-M web site appears to show the wheels featuring the longer bolts as well; I guess they changed the design at some point.

Another issue we found is that some of ends of the rubber rollers weren't cut squarely, which in some cases caused tight spots in their rotation. Our fix was to square the roller ends up on a belt sander, being very careful not to affect the brass bushing.

Naturally, we'd ordered our wheels a day or two before A-M released the revised roller design, and we don't have the funds to purchase the upgrades.

[techedguy]

You can order 1/2 height Nyloc Jam nuts from MSC. We used them on all of our custom Mecanum wheels and so far so good. If we'd used full size nylocs we'd have had problems too. Overnight shipping was fast for some last minute items we needed. If there are 1/4-20 here's a link:

MSC Part Link

Otherwise here's a link to the book page online:

MSC Catalog Page 1942

Hope that helps. It's working for us.

[DonRotolo]

Blue loctite is also effective for keeping nuts from loosening.

[conceptsingh]

our team bought it and it work fine. just make sure that the washer could spin and doesnt get stuck between the gold thingy and roller

[ebarker]

You need this stuff

http://www.mcmaster.com/nav/enter.as...7&pagenum=3105

http://www.mcmaster.com/nav/enter.as...2&pagenum=3183

http://www.mcmaster.com/nav/enter.as...2&pagenum=2827

[Mahekp15]

Ok if you are using chain instead of a striaght gear box try tighting chain or move it away from the bolts/nuts. same thing happened to us.

[Mahekp15]

Originally Posted by John G

Our team has been having trouble getting our mecanums wheels to function properly.
When we tighten the bolts and lock nuts so that the bolt is in the lock part for the rollers, they bind up. When we tighten them so they are not in the lock part of the nut, but still 3/4 of the way in the nut, some of them seem to loosen up and the rollers fall out. Any help for us?

Every one we have fixed this problem!

[jimwick]

We had this problem and just got longer bolts, both for the rollers and for the sprockets/hub.

jim wick