Trick: Drilling Perpendicular Holes
A “Trick of the Trade” from the February
2011 issue of Popular Woodworking Magazine:
Here is a trick that I’ve developed to help keep holes perpendicular to the surface
when drilling by hand, either with a brace and bit or with an electric drill.
I’m not very good at lining up my drill with a try square, so I made a fixture that
I call a “mirror gauge.” It’s made from two pieces of 1⁄2″ MDF – one board is 5″ x
7″ and the other is 5-1⁄2″ x 7″. The two pieces are butt-joined with glue at 90º.
Cut two pieces of inexpensive mirror slightly smaller than the boards, then glue them
to the faces of the MDF with mastic or mirror adhesive. I drew perpendicular vertical
lines in the middle of each mirror with a marker. The lines provide a reference so
you can see when the bit is perfectly straight.
You can also use the mirror gauge for squaring chisels when dovetailing or mortising.
Walter Lees
Tempe, Arizona
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