[Cory]

Originally Posted by DampRobot

Yeah, those two parts are cam followers. I found them on McMaster a month or two ago and had the exact same thought, that they would be great on an elevator. They're a bit spendy though, at about $20 a piece. You can always go with regular bearings on shoulder screws if cost is a issue.

By the way, I really like that assembly. I assume it was designed for a third stage which would interface with C-channel?

For anyone concerned about cost, shoulder bolts aren't even necessary. We use standard cap screws with great results.