My body holder/troji is a permanent installation built with two bench screws and is so critical to how I work for both build and repair that I’m not sure how I functioned without it.
I considered making it free-standing but bench integrated works better for me as with the mass of the bench I can clamp a body and apply a lot of force to the neck joint during resets without anything budging. The coarser thread pitch on the bench screws is also key compared to the finer pitch thread on the pipe clamps I used as a prototype. It allows quick adjustment, just a few turns, to fit any body depth and taper. Both jaws are removable 3/4” plywood with dense closed cell urethane foam padding. They drop in from the top with grooves that sit over the screws. Not visible in the pic is a web of straps connecting the bottom of each jaw that will catch an instrument should it accidentally fall when the vice is opened due to operator error.
Also not present in the picture is some leather padding that normally sits over the exposed portion of the vice screws.
I cannot recall the exact distance between screws but it’s somewhere around 32-36”.
I have a non-padded set of jaws too which allows this to be used as a large and powerful moxon vice which can hold large fixtures and tooling absolutely immobile. When screwed totally shut with the jaws removed it is very low-profile which is important in my small shop.
It is installed on the “rear” face of my bench and so a guitar in this vice leaves the main bench surface free. Often I will be performing some repair on the guitar in the troji and while waiting for a drop fill to cure or glue to dry I can still use the main bench to proceed with setup work etc
