This exercise may be made from any defective piece of regular stock that will dress to at least 1 inch square and 1 foot long.

The piece should be exactly square and the ends exactly alike. Draw lines at each corner 3/10 of the total distance across the side from each edge. To get the distance at which to set the gauge, lay the rule on the piece at such an angle as will give 10

Fig. 122. Octagon.

equal divisions and mark off 3 of the 10 divisions as shown at A, Fig. 123. Set the gauge to this distance by placing the spur in the mark made by the knife point and moving the head up against the side of the piece. Draw the 8 lines, all equally distant from the four corners without regard to the face-marks. Draw the lines lightly, and be careful to leave the lines as you plane off the corners. If you wish to have a very nice piece of work, use a pencil point instead of the spur. (See Fig. 154.)

Fig. 123. Marking 3-10 with a Rule.

After planing the corners test each side at each end to see that all are equal. If you will mark each side with an

X before planing the corners off you will have less difficulty in making the tests.

On larger pieces you can take 7/24 of the distance across the side instead of 3/10.

This is the distance used b y carpenters in squaring timbers and is nearer the correct distance. In planing, the piece may be held in the vise (Fig. 124), or placed against the bench stop (Fig. 125).

Fig. 124. Planing an Octagon in a Vise.

Fig. 125. Planing an Octagon Against a Bench-Slop.