Very cool. Does anyone who uses a vice a lot think this is beneficial, or more gimmicky?
A woodworking vice typically has softjaws and despite the flexible-ish nature of this vice they still would leave marks in wood so not much help in the woodshop.
A metalworking shop typically uses vices to hold work that they are going to beat on with a hammer, lean on it with a pry bar, attack with a torch, and generally use as a super-secure hold while applying a lot of forces to the work. The vice here has a lot of precision moving parts which wouldn't really hold up to that sort of use case.
A machinist vice is a precision tool and the fixed jaw is a reference surface for the work. With suitable stops, one can use a machinist vice to place work into a predictable position time after time ("repeatability"). This style of vice can't do that either.
I could almost maybe see this used for small parts fabrication on a drill press maybe? The OP uses it as workholding while engraving which feels a little contrived and there are other cheaper/faster/easier solutions out there but sure maybe?
No force is intended to be applied at all, beyond gravity.
A dedicated jig is always better, but takes time and effort to create. This thing always works moderately well.
It’s usually a pain to hold irregular parts without a flat surface. In fact, I can’t think of a good way to do it at all.
> It’s usually a pain to hold irregular parts without a flat surface. In fact, I can’t think of a good way to do it at all.
Jigs/fixtures, side clamps, strap clamps, toe clamps, Mitee-Bite-style off axis cams, plenty of options. There are commercial manufacturers of flexible workholding solutions similar in spirit to the OP but those are generally targeted at QC purposes where you'll be running a CMM of some sort over the part and so no reference surface on the fixture is needed: https://engtechgroup.com/technical-partner/hyfore-workholdin...
I’m not sure what mitee bite is but the other suggestions are not realistic. Side clamps wouldn't be able to hold something shaped like a 2D Christmas tree rigidly. Strap clamps are not nearly rigid enough even for hobby grade work. Toe clamps won’t work for anything rounded etc. All of the above can be held with the fractal vise.
I use strap clamps on a hobby mill to hold steel while being machined, they are plenty rigid.
https://www.youtube.com/watch?v=9FVavOy4GUw
Here he's attempting a side clamp design but demonstrates several other solutions commonly used for the home machine shop. Hope you find it helpful!