https://www.thingiverse.com/thing:2064269 machine vice is a great design and needs no improvement. However, it is possible to abuse and over-tighten the vice mechanism. I needed to repeatedly grip lots of delicate parts with the vice and therefore thought a torque-limiting handle might be useful. Also used the opportunity to improve my Fusion 360 skills regarding threads and joints/motion links.

As TheGoofy kindly shared his Fusion 360 design folder, I simply and quickly re-mixed his Centre Gear component to create a new sub-assembly "Centre Torque Gear". This is made up of 3 new components:
Gear Body
Gear Torque Handle
Gear Pressure Plate

Print the 3 parts; using 4 or 5 walls and 20% infill, with adaptive layers at 0,12 or 0,16mm layer height. As these are threaded parts, I choose to use Print "One at A Time" (Cura Special Modes option) for better quality, less stringing etc. Please carefully check your gantry height and clearance envelop if using this option.

PETG or ABS would likely be the best material for all parts, but I used PLA+ for easier printing of the fine threads.

Works great!! see video https://youtu.be/bCZ2q7d6Qtg

Insert a standard 4mm hex key (aka allen key) tool into back of Pressure Plate and insert through the Torque Handle, then carefully start engaging the fine threads. Wind the plate into the handle a few turns, but DO NOT jam against bottom seating. The threads should be a transition fit (but not too loose). At this point, the pressure plate gear teeth features should be approximately 2mm sub-flush from the front flange of the handle.

Offer the torque handle/pressure plate sub up to the main Gear Body, and gently push the parts together. The tri-slotted torque handle flange should flex and snap over the main gear body rim.

Using the 4mm hex allen key and holding the torque handle, carefully wind the pressure plate towards the main gear body until the teeth engage and some resistance is felt. As you wind further, the pressure on teeth increases and thus the set torque of the handle increases.

Loading of the vice by turning the handle CW, is limited by the teeth slipping. Unloading of the vice by turning the handle CCW causes the teeth to lock firmly. If the pressure plate occasionally slips around inside the handle, re-adjust using the allen key.

Do not over-tighten or force the pressure plate adjustment.