This was a fun little project. Something to discover new things.
I was interested in working with a crossed roller bearing in a future design. I ordered one and found a project that would introduce me to working with the element and add some value in the shop.
It’s a simple rotisserie but it mounts to the fixture table.
To be honest. I got lucky with what happened. I had ordered a bearing from China without much of a plan. I just wanted something big but cheap. This arrived to my door for $98.54. Shockingly, It was one of the best sizes that I could have chosen. The 120mm outside diameter just fits within the breadboard bolts (with 0.7mm to spare!) for smaller scale projects and making the best use of components that I have.
“the Lord protects and preserves the simple, defenseless, or childlike” Psalm 116:6
This unit is marked TRH Tai Sheng Bearings RU85UUCC0/P5. It’s pretty cheap, so much so that I can’t find a home page for the company on the internet. I like that these can sometimes be called ‘Robot Turntable Bearings’. These are marked ‘Germany’ which is insane. I’m sure that there is a story with that.
In the demonstration shown, I place 80 pounds of lead 13 inches from the center axis. The system functions free and easy with no discernable friction or grinding. In fact, I later sat on the arm with similar results. That’s awesome for such a small package.
Based on the generic engineering data supplied for the RU85, the bearing should handle 6,631 lbf (29.5kN) static radial load. The axial load should have a static axial factor (Y₀) of 0.44, so 15,062 lbf (67.0kN). I believe that that will be well within the needs I will have.
