Mortises with a Forstner Bit

Why a Forstner?

Forsnter bits allow you to drill overlapping holes, making them a great tool choice for this application. Most drill bits won’t do overlapping holes.

A fence is a must-have

You’ve gotta have a fence on your drill press for this operation. If you don’t have a good table and fence on your drill press, check out this great shop-made version.

Sequence of events

Start by laying out the mortise and choosing what size bit you’ll use. ¼” Forstner bit for ¼” mortises. Set the fence location and drill two holes, one at the top of the mortise and one at the bottom. Then you can start taking out the waste in between those two holes. Hold your material tight against the fence and punch a series of holes, allowing them to overlap more and more with each punch.

The Forstner bit removes A LOT of the waste, but you’ll see small high spots left behind. Your last step is using a sharp chisel to pare down the high spots, and then you’re ready to cut a matching tenon.