what are vise jaws made from
Modifications I made are, The bearings are high speed stainless steel ball bearings in a brass housing, not delrin. The jaws are 440C stainless hardened to 56-58 rockwell, not A-7 or D-2 like on a LAW. Mine will never rust. Vise is made of stainless steel and brass. Delrin used for the drag washers and bobbin rest.
The jaws are often separate and replaceable, usually engraved with serrated or diamond teeth. Soft jaw covers made of aluminum, copper, wood (for woodworking) or plastic may be used to protect delicate work. The jaw opening of an engineer's vise is almost always the same size as the jaw width, if not bigger.