The woodworking vise that I have mounted to the front of my workbench has a steel block that you can slide up above the top surface of the vise. The idea is that you can use this block along with a bench-mounted block (called a “bench dog”) to clamp things on the surface of the bench. The only problem is that my bench is made of 2×4 and plywood instead of solid wood. Since the vise bolts to the underside of the benchtop, the top of the vise isn’t flush with the top of the bench, so this clamping block is useless. I have added wood to the vise jaws, and the top of that wood is roughly flush, but the block is still way shorter than would be useful. Today I changed that.
This is the old,
useless block
This is the new,
useful block
Here you can see the dog bolted to the bench top 
Here’s how you use the two together
I cut a block of 1/2-inch walnut so it had the same width as the block, but was longer. Then, I removed the old block and slid the new block down into the recess. I cut the new block so that when it was retracted, it would be below the top surface of the vise jaws. Then, I drilled the block so it would accept a 5/16″ tee nut. I made a new knob by adding a nut to a 5/16″ x 1″ bolt. Now, I can raise and lower the block, and secure it in place by tightening the nut. I would have re-used the knob from the old block, but it seems to be some kind of metric thread.
The dog is a piece of scrap wood with a hole drilled through it and a counter-sink to put the bolt head down below the surface of the block. This is important to make it more difficult for a tool to hit the metal of bolt while working on a clamped piece. I drove a 1/4″ threaded insert down into the bench so that I can bolt any old piece of material to the bench top, whenever.
The walnut block is maybe a little flexible for this application, but it’s certainly better than ol’ useless that it replaced. I can’t believe I put off making this modification for so long. It was immediately useful. Maybe in another few years I will barter with a metalworker for a metal block, now that I know the dimensions I need.
