Good idea.
I immediately noticed how high the knob stands, which will severely collide with the wheels, particularly given how close the knob is to the front of the jaws. My first thought about how to solve this would be with a socket head screw, like a set screw. So, rather than having a knob on it at all, one would need a hex key to insert into the socket to tighten and loosen, then remove and both sides of the jaws are totally clear. Slight bother having to handle a separate tool to operate, but I think something that users would tolerate to have the self-centering function.
The steep angle on the topsides of the jaws look like they will limit how small an angle that may be achievable. This may have been considered in the design, so may not be a problem, but they just look too steep to me.
I'm sure there needs to be adequate thickness to support the threads, particularly if the material is aluminum or zinc. Use of threaded inserts made of stainless could help. If I were doing this, I would first try the [urlhttps://www.stanleyengineeredfastening.com/brands/optia/heli-coil]"helicoil" style threaded inserts[/url]. I have them as small as 1/4" long. These are meant for repairing stripped threads in metal, particularly engine parts, but I use them extensively in woodworking. I have found them in 6mm at a local large hardware chain store, but
online supply houses, like McMaster-Carr offer a vast array, plus the tools for inserting them.
The photo posted here shows removing a helicoil threaded insert from some wood, but the remover could just as well be the insert driver tool.
Making such a right/left, turnbuckle style screw with a socket head driver would be challenging, for sure. I am noodling that in my brain as I type. Turning down one end of a typical set screw and then turning left hand threads on that end, maintaining the thread pitch (M6) on a smaller diameter could be done, but then matching those with threaded inserts could be a problem, as they would be non-standard, left hand, which I doubt is available in threaded inserts. That might be resolved by making an insert, but that has its own challenges.
M6 left-handed threaded inserts are available, but only at this site, only in 9mm length (0.354") but that could be a very suitable length.
I just noticed the turnbuckle screw in your jig is a fair bit larger than M6, so maybe threaded inserts are available in more varieties that I've discussed above.
I am curious about how the jig shaft mounts into the jaw set. The first frames in your video appear to show it canted a bit, which suggests there may be some movement in that joint, which I think would not be good. Hard to tell, however, as the jig is not shown clamping a blade or in use.
I'm sure you will keep us posted.
Rick
