Adjust fence and repeat until holes are identical
To center the bit on the workpiece, drill a shallow hole on a piece of scrap that is the same thickness as your piece. Flip the scrap piece around and drill a second hole to see if it lines up with the first. If not, reposition the fence and repeat the procedure.
of Forstner bits, you can use a brad point bit and drill non-overlapping holes, see box on opposite page.)
LAYOUT. But before you chuck the bit in the drill press, the first step is to lay out the mortises on the work-piece, see Step 1 page 15. You could get by just laying out the ends of the mortise, but I usually take the time to lay out the sides as well. This doesn't make it any easier to drill the holes, but when using a chisel to clean up the mortise later, the lines help you see what you're doing a lot better.
SETUP. With the mortises laid out, it's time to set up the drill press. This involves setting the depth stop and adjusting the fence, see box at left.
DRILL OUT THE WASTE. The first step in drilling out the waste is to drill a hole at each end of the mortise, just inside the layout lines, see Step 2. Then to remove the waste in between, you can drill a series of overlapping holes along the length of the mortise, working from one end to the other.
When drilling with a Forstner bit, avoid the temptation to ram the bit into the workpiece full force. Instead, ease it into the wood, letting the cutting edge of the bit do its work. (Shop Note: If the wood burns, adjust your drill press to run at a slower speed.)
The thing to remember when drilling with Forstner bits is that they don't remove chips like common twist 01* brad point bits do. So rather than drilling the hole in a single stroke, you'll want to work the bit in and out several 1 imes with each hole, until the depth stop causes the bit to "bottom out." Then just back the bit out, nudge the workpiece over, and drill the next hole in the same manner. And keep this in mind when drilling. The closer the holes, the less clean up you'll have to do with the chisel later.
As you can imagine, drilling these overlapping holes creates quite a few wood chips, and it won't be long-before your drill press table is covered. Just make sure one of these chips doesn't fall between the work-piece and the fence, or it will throw off the alignment of the holes.
To prevent this, I like to keep a small bench brush handy so I can brush away the chips after drilling each hole. (A quick blast of compressed air also works well.)
SQUARE UP THE MORTISE. Once the bulk of the waste is drilled out, the next step is to square up the sides and ends of the mortise with a chisel.
Even with overlapping holes, there are going to be little jagged "peaks" along both sides of the mortise left behind by the drill bit. So the task now is to pare both sides of the mortise smooth and flat, see Step 3.
To remove the peaks, I like to use
A stop block will come in handy if you need to drill mortises in the same location in several pieces.
IOn the edge of the workpiece, use a sharp pencil, a ruler, and a square to carefully lay out the ends and the sides of the mortise.
Was this article helpful?