lsaguy wrote:
The problem could be that the threads have galled, i.e. there is some material transfer between the two parts. A 50/50 solution of acetone and automatic transmission fluid is about the best penetrating lubricant I know of. It only takes a drop or two. If you decide to try it make sure to test it on an unseen surface to make sure there's no reaction of any surface finish on the parts that might react to the acetone.
Rick
I think the screw threads have been corrupted by repeated attempts to reattach the twist leg lock