Drill Straight Holes Redux

Recently I posted a tip I use for drilling holes perpendicular to a surface using two squares placed 90° apart. Well, someone I’m proud and privileged to count among my friends and whose opinion I respect, Carl Bilderback, called me to complain that keeping sight of two squares was not working for him.

Carl offered two methods that he has used to drill holes perpendicular to a surface. One is to use a piece of aluminum angle cut square to the legs. Place it so your drill bit is inside the 90º angle right at the corner. Keeping the bit parallel to both legs of the angle will get you a straight hole.

A 1, 2, 3, block used to drill straight holes.

A 1, 2, 3, block used to drill straight holes.

The other method offered by Carl was to use the corner of a square block of wood placed close to your drill bit. Thinking about the square block of wood brought to mind a machinists 1-2-3 block. Instead of milling a block of wood square why not simply use one of these! As can be seen in the pic above I tried this method using one of a pair of 1-2-3 blocks I have and it worked well.

If you are unfamiliar with 1-2-3 blocks they are a precision tool used by the machine trades for all sorts of things from layout to machine tool setup. I use mine in the wood shop mainly for layout. With a pair of these blocks you have precise layout from 1″ to 6″ in 1″ increments with no setup or adjustment needed and no scales to read. you can often find these useful blocks at flea markets or they can be purchased new here.

After trying these other methods of drilling perpendicular holes I still feel more comfortable with the two square method. If you have had trouble with this method try one of Carl’s methods. They may work better for you.

As always, thanks for stopping by and feel free to leave a comment.


Professional furniture maker and restorer. Dealer and collector of vintage and antique woodworking tools.
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4 Responses to Drill Straight Holes Redux

  1. I have a piece of brass angle that I inherited from a machinist friend. It’s 1 ½ x 1 ½ x 4, and is perfectly square on one end and 45º on the other. Really handy for aligning drill bits…

  2. rondennis303 says:

    I really like the 1-2-3 block idea! I’ll have to keep my 1-2-3 block in its storage box with my drill bits.

  3. Steve says:

    I I have a hole to drill I need absolutely perpendicular I make a drill guide in the Drill press out of Hardwood scrap I always have oak cut-off in my scrap bin… This works really well for making dog holes in a work bench.

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