Hey yall, I put together this quick little video showing how I made a guard jack for my hidden tang knives. This thing allows the maker to apply force on his/her knife's guard; pushing it into the shoulder. In my case I've used it to check fits without having to hammer the guard, however, I've seen some people use these to press fit their guard over the shoulder on softer materials.
I've also seen some makers use these guard jacks to hold the guard in place while it's epoxied to the knife or soldered.
Anyways... this is how I made one. Cheers!