The Square, Mitre-Square and Bevel: One Tool for Every Angle a Carpenter Needs

"A, is the stock of the square, B, the steel arm projecting from it in the ordinary manner. C, is a smaller arm pivoted to the stock at a, which when not in use, is closed up and shuts into a slit in the back of the stock as seen dotted in black in Fig. 1. To the inner end of this arm which traverses within the stock, is attached a pointer or stop b, which moves in the circular slot c, on the sides of which are marked scales to the figures on which the pointer b may be adjusted, causing the arm c, to form with the back of the stock at d, any required angle." "The above described improved tool may be used, 1st as a common square, the edge D and arm B being at right angles to each other. 2nd as a miter square for a square miter, the raised edge at D, forming with the ends of the stock at E, and F, angles of 45 degrees."

**Stock.** Plane a hardwood stock 20 cm × 6 cm × 18 mm, and glue a strip along one face at the inner edge D so it stands proud as a guard. Cut both ends at 45° to the inner edge with the saw and protractor, as E and F. **Blade.** Cut a 25 cm blade from aluminium flat bar, slot the stock's end to take it, and fix it with two screws at right angles to D. Test it by the flip test and adjust until it is true. **Bevel arm.** Cut a slit along the back of the stock to take a 20 cm arm of flat bar, pivot it on a screw a, and cut a circular slot c through the stock about the pivot. Fix a short pin to the arm's inner end as the pointer b, running in the slot. With the protractor, set the arm to each angle to the edge from the notebook, for 5, 6, 8 and 12 sides, and mark the slot at the pointer for each, and fit a wing nut on the pivot to lock the arm. **Test.** Set the arm for six sides and mark and cut six pieces of pine at that angle. Glue them into a hexagon and check the joints for gaps.

**A. McKenzie** of Boston, Suffolk County, Massachusetts, received US 17,106, dated 21 April 1857; he signed as Alex McKenzie. The stock was made thicker at its inner edge D; the arm C could be thrown further round to measure the supplement of a mitre, from the inside of a box, with the figures x on the outside of the slot; and it could be locked by the screw at a. His claim is the try square, mitre and bevel blade arranged together, the blade hung so as to project on the side of the stock opposite the square's blade and to continue the 45° mitre. **Honest limits.** Hardwood and aluminium flat bar stand in for his stock and steel arm, and the scale is marked from a protractor. The notebook gives ideal angles; your joints show how close the tool holds them.