Response greatly appreciated. I have and use the top 2 tools in the set pictured in the Harbor F set. The bottom one w red handles must be the one. I find the springs that need to be compressed require a great deal of force in order to push in and insert the locking washer. That's why I have tried to use vise grips w/o success.

Any advice. Taking the articulating arms off in order to use a vise doesn't sound good. The center attachment pin would be hard to secure w the backing plate there i the way.

Any experience w that tool in the HF set?