Miter saws are some of the most accurate saws available and are perfect for complicated cuts like mitering crown molding and other finish carpentry. You can reinforce this accuracy by mounting the saw to a bench. This will stop any movement, provide extra stability and ensure that the saw doesn't bind. Miter saws have holes in the feet for mounting. Sometimes it may not be convenient to mount the saw to a work-bench. In that case, you can mount the saw to a sheet of plywood which will provide stability with portability.
Things You'll Need
Workbench or 1/2-inch or thicker plywood
Drill and bits
Screws or bolts
Screwdriver or wrenches
Place the saw on the work bench or piece of plywood and mark the four saw mounting holes on the surface. Often, there will be two possible mounting hole options, of differing sizes, for each of the four points. This is to provide flexibility on size of fastener.
Drill the holes for screws if you are mounting to a work bench. Drill holes for bolts if you are mounting on the plywood. Flip the plywood and countersink for the nuts so that the bolts don't protrude and the plywood is flush with the surface on which it will sit. Then attach the hardware, mounting the saw, using the appropriate screwdriver or wrench.
Clamp the plywood-mounted saw to a work bench before operating the saw. Clamp it at the bolts, rather than anywhere else to avoid interference with the saw's operation.