@913B Lets see if I can answer the questions posed:
Self tapping screws, did not feel like getting all pretty at this time. Some times down and dirty is the proper application. Yes I could have drilled out the tube, mounted a few weld nut plates and done it all, fancy. But why in the end, not like I am getting paid to make it work, just eliminating a very frustrating operational issue. In that you can't move with a small push of a finger. Now I can, maybe not a finger, but certainly not a heavy hand.
I have a jig I made that I clamped to the tube with the lift in the upright position. Top hole is 4.5 inches away from the floor.
As far as weight, I am not worried, 101 pounds is a single frame, with my extension lets call it 150. Divided by 4, and we are seeing 37.5 pounds per corner. It is a steel ball bearing, it will not be crushed by the load. And the backer that ball rides on, is backed by the tube it is screwed to. For the amount of movement it will have on my shop floor, I doubt I will wear it out. If I do lessons will be learned and fix will be applied. And testing will begin again.
Maybe the next iteration will have a solid steel tooled /hardened bearing surface. Doubt I will see the day. And I have a complete set of replacement units off another out feed setup.