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Squares 101

 

It is pretty well impossible to do any assembly without at least one accurate square, not only do they indicate your corners are bang on, most also have scales for measuring lengths and widths. There are three basic types to have in your tool kit, a steel square, a combination square and a try square.

 

 

Framing Square

framing square

With this tool it is possible to layout and measure just about everything in the construction of a house from the basement stairs on up to the attic rafters. It may also be refered to as a steel square or a carpenters square. The most common size has a 24" blade and a 16" tongue, however there are smaller sizes available but like some cheaper versions of the larger style they do not have the framing tables stamped on them.

The Steel Square and How to Use It.

Try Square

try square

These squares have a steel tongue fixed into a wooden handle, they range in size from 3" to 12", some have inch scales on them others are blank. They are very handy for furniture and cabinet making as they are small enough to fit in confined spaces.

Combination Square

combination square

This is a two peice unit with a head that slides along a steel blade, it measures both 45° and 90°. Many models come with a level built into the head. This is an excellent first tool for anyone starting out. There is a broad range of choices, from very inexpensive to very expensive, a good quality one somewhere in the middle will be adequate for most. This aquare has many uses, as shown below.

combination square uses

 

The first thing to do with any square is to check it for accuracy, this should be done in the store before purchasing it if possible.

Checking for Accuracy
 
To check a square for accuracy draw a line on a board, invert the square, if the square blade is parallel to the line the square is accurate. Use a sharp pencil, or lay a strip of masking tape on the board and cut the tape with a utility knife against the blade of the square.
 
 
Check both the inside and outside arms of the square,
sometimes the blades are not parallel.
Framing squares can be adjusted

If the square is less than 90° strike the inside of the corner with a center punch, if it is more than 90° strike the outside of the corner.

Triangles

These are available in in many shapes and sizes in various materials, the two shown above, a double 45° and a 30° - 60° are the two shapes used most in laying out patterns.

Sliding Bevel


This tool has a adjustable blade which can be used to transfer angles to mark on a board to be cut or be used to set-up a power saw. It can also replace a try square but caution must be used so that the blade is not accidentally knocked out of square.