Jim Conway wrote:
The one's I have need to be loosened/tightened using a wrench each
time
you want to use them. I find them to be quite useless when they are
up
as the machine's vibration is enough to loosen the nut holding them
up,
and constantly causing them to drop. fuhgeddaboudit!



Lock washers or both them and locktight should solve that problem.

Harry K