1. The try-square is composed of a beam and a blade set at right angles to each other. (See Fig. 15.)

2. It is used, (a) to test right angles, and (b) as a guide for the knife or pencil in drawing lines at right angles to a surface, usually across the grain of wood.

3. In laying out work or testing angles, always keep the beam against either the face side or the joint edge of the work.

For an explanation of the terms, "face side" and "joint edge," see Rules for squaring stock to dimensions, Chapter VII (Squaring Stock To Dimensions).

4. In laying out work with a try-square and knife the lines should be run so that they will not show upon the finished surfaces.

Try-Square

The blade is graduated (See Fig. 15) so that lines can be started and stopped at any desired distances. Therefore, draw the cross lines first and the gage lines afterward in laying out mortises, tenons, gains, etc.

Notes:

(1) The blade of the try-square can be, and often is used as a straight-edge or as a rule. These are, however, accidental and not fundamental uses. There are other tools for these purposes.

(2) One large try-square is very useful and should be found in every well equipped shop.