Switchblade
Bearcat
I know they are various ways of replacing a main spring on a single action, from a vice and pliers to more elaborate methods. I thought I would show a simple tool I made to make it easier for me. I used a 5/8" dowel cut a slot and chucked it in my drill press. Use a 1/2" if that is the largest your drill press will take, might consider cutting slot only as wide as necessary.

