Even though they’re sexy, benchtop mortising machines aren’t the only power-tool option when it comes to cutting square-shouldered mortises. A drill-press mortising attachment can be just as effective and it costs a lot less. I’ll show you how to tune any out-of–the-box mortising attachment so it’s easy to install and a joy to use.
Mortising attachments are available for almost every drill press. Although they vary in appearance, they all have three basic components: a fence, a chisel holder and a hold-down. Upgrading these parts to stabilize the workpiece and operating the drill press at the optimal speed are the keys to success.
I get first-class results with my
tuned-up mortising attachment. That
means I don’t have to store a large,
heavy mortiser that I would only use
occasionally. On the drill press, I can
slow the speed way down, too, so
the bits don’t screetch and smoke.
Drill press mortising is slower, but it’s
much more pleasant, a lot quieter
and much less nerve-racking
than using a mortiser.
Square mortises require special
bits, which can be bought individually
or in sets. Inexpensive bits usually
won’t stay sharp as long (see “Start
Sharp, Stay Sharp,” below), but dropping
one on the concrete floor won’t
give you a heart attack, either.
Click any image to view a larger version.
Mortising bits cut
square holes. The
auger bit fits inside the
chisel and protrudes slightly.
During operation, the auger
drills a round hole and the foursided
chisel squares the corners.
Cut side by side, square holes create
mortises (see photo, left).