These are my 5/16" tubing insertion plyers. They have a pair of vice grips with a split, threaded rod adapter to grip the tubing and a pair of fingers to hold the fitting. I’ve modified them to make them line up a bit better for the way I use them. I’m thinking about taking off the plate with the fingers and making the slot smaller to better fit the fittings I use. This tool is an absolute must have if you’re going to build a vacuum tube system.
I bought these at CDL (catalog)but it doesn’t look like they sell this model any more. The closest one I see in the catalog is pn 6623157 which has an added knife for some reason.
As built that one drove me crazy. The slot was not alligned with the center of the straight coupler. I cut it off and welded it in the correct position. I would really like the slot to be narrower so that it catches the small couplers like the flat hooks better andI would like them a few millimeters longer and with a bit more of a bend in it. It’s an easy fix but it’s one of those things that I just never seem to get around to.
It works really well as it is but it would be that much better with a bit of modification.