How to use our favorite setup tools
By Richard Tendick
Every woodworker falls in love with
some favorite tools now and then. I
count on my faithful set of precision
squares every day, from milling the
first rough board to installing the last
brass hinge. They’re the solid foundation
of every successful project.
When I was a young woodworker,
though, my first affair with an attractive
square ended in bittersweet disappointment.
This tool was a real beauty.
It had a rosewood handle inlaid with
brass and a blued steel blade.
As I gained experience, however, I
realized my parts weren’t truly square.
I blamed everything but the tool itself.
One day I compared it to a friend’s
square. He was a fussy machinist, so
his square was true. Mine was way off!
My tool was too inaccurate for critical
work but too beautiful to throw away.
My pal clued me in to the best features
of a good square, how to test it
and how to use it—hard-earned knowledge
I’ll now share with you.
A Classic Precision Square
The most reliable and useful precision square in
my shop is a Starrett 12-in. combination square. Many other finicky
woodworkers have told me that they, too, treasure one
of these tools. I put my initials on my square and keep
it safe in its own special drawer compartment.
Many combination squares aren’t very accurate, but this one is made to extremely precise tolerances and is
individually checked before it leaves the factory. A
good 12-in. square, like this one, should be no more
than .002 in. out of square at the end of the blade (for
comparison, a piece of paper is about .003 in. thick).
Look for a published tolerance this small when you
shop for any type of precision square.
Click any image to view a larger version.
How Square is Your Square?
No matter how fancy a square looks, when it comes to
accuracy, I’ve got to see it to believe it. Inexpensive models,
like a 12-in. fixed-blade machinist’s square, should always be tested. Here’s a new
variation on an old method of testing any square.
1. Cut a line down the middle
of a piece of tape attached to
a melamine board. The bottom
edge of the board must be
absolutely straight. Check the
board’s edge against the top of
2. Peel off the right-hand side
of the tape. The contrast
between the blue tape and
bright white melamine makes
the precisely cut edge easy
3. Flip the square and butt it
against the tape. They should
match perfectly. A gap at top or
bottom shows you twice the
amount that the square is in
Two First-Rate Squares for Precision Setups
I always set up my machines with one of two
kinds of precision squares. For the tablesaw, I pull
out my 12-in. Starrett combination for its long stock
and adjustable blade.
For the bandsaw, jointer and nearly everything
else, I turn to a pocket-size 4-in. double square. Its blade slides just like
a combination square, so I can use it for layout
work, too. A 4-in. machinist’s square is a less expensive
How to Square a Jointer Fence
I’ve never really trusted the 90-degree stop on my jointer’s
fence. Every time I tighten the lock-down bolt, the fence
shifts position. Lots of other jointers have this problem,
too. The only solution is to begin with the fence slightly
out of square and stop tightening at the point that the
fence actually is square.
How to Square a Miter Gauge
Do you rely on the positive stops on your miter gauge?
I don’t. To accurately adjust my gauge, I hold the large
square against the gauge’s bare face, raise the saw blade
full height, place the square’s blade between two saw
teeth and extend it almost the full width of the saw blade.
How to Square a Saw Blade
I used to simply stand my square on the table, but a good
pal showed me this method. It’s twice as accurate,
because you’re checking twice as much blade. You have
to see down into the bowels of the saw, so a flashlight is
really handy. As with the miter gauge, the square’s blade
runs between the saw’s teeth.
How to Check an Edge for Square
Accurately setting up your machines is only half the
battle. The acid test comes when you actually test the
boards themselves. I always use my 12-in. square for
checking boards that I’ve crosscut on the tablesaw. For
checking a jointed edge, I pull out a smaller square.
The easiest method is to look for light between the square’s blade and a jointed edge. Sometimes
this isn’t practical, though. It’s hard to hold a long or
heavy board so that there’s a good light source
behind the square. I really can’t trust what I can
barely see, so I rely on a feel test with a small, lightweight
square that’s easy to balance.
1. Firmly rest the square’s beam against the board’s left
face. Lower the blade to the jointed edge. When it contacts
the edge, try to rock the square. It should nest perfectly.
If it doesn’t, you’ll know the left side is high.
2. Rock the square on the other side of the board. Now,
you can tell whether the right side is high. I always
check both sides before I’m satisfied that my boards are