Uneven Thrust Loads on Needle Roller Bearings

[Jay TenBrink]

[quote=M. Krass]or "How I Need to Make A Turntable That Will Not Bind."

mechanism that rotates about a vertical axis and I'm worried that the enormous attached moment arm will cause binding in this vertical pivot joint.

We used a bearing from Kaydon for this very same application on last year's team 494 Martian robot (it had a turret and elevating arm). It was a turntable bearing that we mount in an aluminum disc that gives a a sort of "lazy susan" platform that will take well in excess of 1000 in-lbs of torque. You can mount whatever you want on this platform .

We cut teeth in the outside of the disc and drive it with a window regulator motor to get our azimuth control.

[Madison]

I know you're all perched at the edge of your seats awaiting the solution that was found for this problem.

In the end, we lucked out and found a widely available surplus mechanism that was used to rotate satellite dishes into alignment. At ~6 lbs., they're heavier than one might like, but they're substantial enough to take this load without a problem and include gearing to slow down the rotation to a manageable speed.

While I typically like to design from scratch, this was a clean solution to a sticky problem that freed up our resources to tackle some other pressing issues.

Thanks for everyone's suggestions and help.