Re: pic: Mecanum Musings
 

Sure thing. Start with a center line that will serve as an axis to revolve the roller around. Next, draw your edge lines on the left and right edges of the axis. Put a third in the center, higher than the first two. Draw two arcs connecting these outer lines to the center line. Let me know if this is confusing and I can upload a drawing for you.

They're quite solid as they stand, but I don't like leaving a wheel uncovered for any reason. For that reason I'll probably enclose the wheels, most likely in 1/8th aluminum sheet on which the bumpers will be mounted.

Re: pic: Mecanum Musings
 

I believe I understand what you are saying, it is similar to what I do as well, but a picture would not hurt... thanks!

Re: pic: Mecanum Musings
 

Well, here's a Paint version... I don't entirely feel like booting into windows right now, so I can swap this image out for a screencap of the sketch some other time.



Then you revolve it around that bottom line. After that you put a hole through the center for the bolt, then put recession into the roller for bushings.

Re: pic: Mecanum Musings
 

Yes i'm completely with you there.

To be a little more specific, I was referring to how you designated the actual arc on your sketch. Was it simply a large radius? A spline? If so, what did you use to define that spline, etc... Any more info would be awesome! Thanks again

Re: pic: Mecanum Musings
 

Gotcha. It's drawn as a Center Point Arc. The arcs were each 5 inches in radius (I think. I might be off a little.), and the entire roller is 2.75 wide. I'm still doing some math to see if really using an Arc is the right move. I might end up moving to a spline, who knows right now. I do know that we'll be pouring our own wheels into molds that we get 3d printed!

Re: pic: Mecanum Musings
 

Funny you say that....I use splines when I've designed mine

I actually have my wheel 3d printed already and am making a silicone mold of it, and then using that mold to cast my own hubs and rollers!

Re: pic: Mecanum Musings
 

I would strongly suggest that you make your rollers out of some non-lubricating plastic, then dip them in a rubberized coating to make them sticky. You can get the coating dirt cheap at any hardware store (it's what you dip tools in to rubberize them).

I say that because machining softer grade rubbers can be a real headache for the machinists. They tend to tear - even the harder durometers. So they end up having to freeze them then rush them to the lathe to get them done before they thaw. Like I said - real pain in the neck.

Plastic would be easier to machine, and in the end probably it would probably be cheaper too.

A step up from that would be to have a machine shop machine a female mold that you could pour your own rollers from. That'd be cool and not too hard - heat plastic in pan till liquid and pour in. A bit like pouring those old lead army men into casts.

Re: pic: Mecanum Musings
 

From what he said, I believe he is going to do some sort of casting.

Re: pic: Mecanum Musings
 

In the past our team has had molds 3d printed by the local community college. We would probably do the same this year.