More details on that tester (twas my static tester at Clio you saw as well as the comments illusionist looked up, thanks).
The base was just a cross of balsa pieces to sit on the scale stably, weighted enough to make sure it stayed put, but was within the scales limits.
In the center was a bearing like this: www.a2zcorp.us
look under model supplies, thrust bearings, you want the small white bearings, second row, on right I think. Item code is PA001
Note, it was installed so the wide end was down. I used a length of 0.032 wire, bent a T on the lower end and added a teflon washer between the T and the bearing. The idea is to minimize friction in this bearing because it won't be there in real life.
The upper end was glued into a fixture that fitted the helicopter I built last year so it could be attached and removed. You could just as easily attach it to a permanent motor stick that you attach the rotors you are testing to and change them out as needed.