Posted by
Easy WoodCraft on
Jan 25, 2016
Try squares have long been a mainstay of the woodworker. We use them to lay out and mark boards for joinery, and to check edges to make sure they're truly square. A try square consists of a metal blade and either a wood or metal stock. Most quality wood stocks have the edges faced with brass to reduce wear. Although an engineer's square (see
Engineer's Squares) does the same job as a try square, with a higher degree of accuracy, I still like the feel of a wood handled try square; but when accuracy is critical, I'll reach for an engineer's square.
A specialized version of the try square is the miter square (
inset). It serves the same function as a try square, but the blade is inset in the stock at 45 degrees for checking and laying out miters.
Checking a try square
Just like any other layout took if a try square isn't accurate, it's not worth much. To see whether a try square is actually square, place the stock up against a known flat edge. Then draw a line along the blade and flip the stock over. Align the blade with the line you just drew—it should be in perfect alignment. If not, you'll have to adjust either the stock or the blade by filing it down. (For a nifty alternative to this, see the sidebar below.)
ADJUSTABLE SQUARES
Even though I prefer a try square with a wood stock, these can go out of square over time. Thats because the wood in the stock is constantly moving to react to changes in relative humidity. This can loosen the rivets that hold the blade in place, allowing it to shift out of square. Bridge City Tool Works produces a set of adjustable squares designed to get around this problem. You can tweak the angle of the blade with an Allen wrench.
Checking an edge for square
The most accurate way to use a try square when checking for square is to position the blade of the square against the edge of the work-piece. This lets you position the work-piece so that light can shine through from behind to indicate any gaps. The less desirable method is to place the blade on the face of the work-piece and slide it up until it's near the end of the work-piece (
inset). It's difficult to see any gaps this way; avoid it whenever possible.
Accurate marking
If you've ever watched a draftsman in action, you'll note that he always places his pencil at the exact point where he wants to draw a line, and slides the square up so it butts up against the pencil. This might seem like a no-brainer, but over the years I've watched a lot of woodworkers do just the opposite—set the square on the mark and then draw the line. The problem with this is that it doesn't take into account the distance between the square and the center-point of the pencil lead.
ENGINEER'S SQUARES
Engineer's squares are similar to try squares except both the stock and the blade are metal and they're manufactured to much higher tolerances. I use them whenever accuracy is critical, and I've found the small size indispensable for checking for square. As a matter of fact, the small one shown here is a constant companion to the tape measure and 6" metal rule that reside in my aoron pockets.
Thanks for reading Try Squares. Please share...!
