All of our vises at school have cast iron jaws that can damage work and tools. So, I am in the process of lining them with wood inserts to save our rasps and gouges from damage. This also allows our students to have a better grip on the curved and rounded objects that we clamp, mostly mallets and spoon blanks. In order to provide an even better clamping (vising) agent, I recently introduced a second line of defense for the jaws and workpiece. These are thick rectangular paper pulp mats that I cut from a material called *Homasote.
Homasote is cheap, readily available and easy to cut into any form. We got many of our Homasote scraps from the sidewalk, like so many of our projects supplies, when they were tossed out at the end of a house renovation. Since I am an avid recycler, we put them back to work in the shape of jaw liners and bench mats. The material is used in the building industry and is made from recycled paper pulp pressed together to make a ½” or so soft fiberboard panel. It is rigid enough to hold its pulp matrix for years under much abuse, and yet malleable enough so it can be depressed to embrace the contour of round(ish) objects in the vise or under a clamp. This characteristic — soft but rigid — helps in spreading the clamping pressure more evenly from the jaw face to the object’s surface, thus reducing the uneven forces that the vise’s rods have to endure, while at the same time provide a much better purchase on the object.
I cut the liner pattern on the band saw, including the three coves for the vise’s screw and rods. These recesses help in hooking the liners inside the vise to prevent them form moving or falling every time we open or close the vise. We do not use any glue or fasteners to keep the liner in place but this is definitely an option for a more permanent approach. We also use this material to cushion workplaces when clamping with c-clamps or f-clamps by cutting it into strips and tucking it over the clamp’s steel pressure pads.
Lastly, a 4×8 sheet of Homasote panel cost around $29 in the home centers so it is very affordable too.
*Full disclosure, I don’t work for the company that makes Homasote nor do I receive any payment for naming this product in this blog, I just think its good stuff.