1. The T-Bevel is composed of a beam and an adjustable blade. (See Fig. 15.)

2. It is used to lay out and test angles other than right angles. Reference Work: Learn how to set the T-bevel for 45°, and for 30° and 60°, using the steel square as a guide. Hints:

(1) The angle that the diagonal of a square makes with its sides is an angle of 45°.

(2) Look up Fig. 14, Chapter II (Drawing), and see if you can apply the figure so as to use the steel square to set for a 30° angle.

Fig. 15. Sliding T-Bevel.

Note that in this figure the hypotenuse is the diameter of the circle, while one side of the triangle is equal to one-half the diameter of the circle, and that one angle is 90°, the angle of the steel square. If you fail to see it, ask some good mechanic to show you the trick.