Centering and Driving Flat Belts

For a long time, I’ve seen teams use flat belts to considerable success (341 in 2012 and 2363 last year), and in an effort to pick as much as I can before kickoff, I was wondering how teams go about driving flat belts?

I know that you need a simple crown to keep the belts centered (so you can run them sasn pulleys). Any tips on how to create these crowns/what works super well? Is there a specific type of tape that the flat belts work really well with?

  • Sunny G.

Last year we were one of the few teams at the Granite State Regional that could pick up frisbees reliably from the floor. We used a flat belt system.

We found the necessary rollers at the local True Value hardware store! They were in the section of the store that had furniture rollers and glides. They had a convex profile. They were mounted in sort of a foot, but we just drilled that out and used the rollers. They worked just fine with a 1" urethane flat belt.

Could you post a picture of the part, preferably on the robot but doesn’t have to be.

Flat belts worked really well for us on our collector:

We used McMaster flat urethane belt with this part number: 6075K14

To make sure the belts tracked well, we wrapped crowns of tape over the 1/2" shaft (which raised the diameter of the “pulley” to the minimum diam. specified for the belt product). We usually wrapped a few layers with the upper layers thinner in width to create a gradually crowned shape. In our experience, the belts have run great as long as the crowns on each shaft are properly aligned to each other.

I will edit with the exact name of the tape product we used if I can find it. It was in the electrical tape section, but it is not smooth on the outside as most electrical tape is. Instead, it was black and fairly sticky on both sides, which made it pretty good for our purposes. We acquired it from OSH, a local hardware store chain, but I cannot find the product on their website.

Hope this helps.

I think the tape used was 3M mastic tape. That stuff is like magic. Feel free to PM Dustin or Jared to confirm though.

We used plain old electrical tape.

Would it be possible for someone to posts a few pictures to show how it attaches with the rollers. My team has wanted to try this before, and this would be a nice help.

Decent picture here:

You can see there really isn’t much to it. Wrap the tape while spinning the roller, and wrap more densely in the middle. It doesn’t take much to keep the belt centered.


In the various incarnations of our arms and handlers we drove the flat belts in a couple different ways.

  1. using rollers made from 1" OD aluminum tube. Where the belts were located, we wrapped the rollers with 1/4" wide strips of 1/16" thick bump-on adhesive backed urethane from McMaster.
  2. using 1" wide crowned rollers that were 3D printed. STEP files for these parts can be found on the CAD models found in this thread. We made rollers for both 1/2" hex shaft and 3/8" round keyed shaft.