Benchtop space-saver: Removable mounting boards
When you want to use the whole top of your workbench, a permanently mounted vise or grinder just gets in the way. Free up space by mounting your grinder and vise to a double-thick piece of 3/4-in. plywood and hanging them on the end of your workbench until they're needed.
Cut four 20-in.-long x 12-in.-wide pieces of 3/4-in. plywood. Glue and nail them together in pairs to make two 1-1/2-in.-thick slabs. Transfer the location of the mounting holes on your vise and grinder to the plywood. Use a 1-in. spade bit to drill a 1/2-in.-deep recess at each hole location.
Then drill through the plywood with a 3/8-in. bit and mount the tools with 3/8-in. bolts, washers and nuts. Position the recess on the side of the plywood opposite the tool to ensure a flush surface.
We screwed a double-thick piece of 3/4-in. plywood to the end of the workbench to make a sturdy mounting plate, but your workbench may not need this. Any strong, flat surface will work. Drill two 1/2-in. holes into each tool holder and mark matching hole locations on the mounting plate. Drill 3/8-in. holes at the marks and attach 3/8-in. bolts with nuts and washers. We recessed the nuts in the mounting plate so the tool holders would sit flush, but this isn't necessary.