The hand tools of pattern making are more or less familiar as those used in carpentry work. Attention will be called to a few special tools and features.

Saw Teeth. - In sharpening saw teeth, the file should be held at an angle to the plane of the saw blade so that the teeth will present an appearance shown in Fig. 104. The teeth should also be "set" to keep the wood from binding the sides of the saw. This is done by bending the teeth marked c slightly to one side of the plane of the saw, and by bending those marked b slightly to the other side. In this way the saw cut is slightly wider than the blade thickness of the saw.

Fig. 104.

The teeth of circular saws may be "set" or may be "swaged." In swaging, the teeth are not bent to one side, but the tooth end is expanded by a swage and hammer so that its cut is wider than the thickness of the saw.

Fig. 105. - Trammel Points.

Trammel Points. - For describing arcs of large radii, a pair of trammel points, A and B, are mounted on a bar of wood or metal as shown in Fig. 105. These points may be clamped at any position along the bar.

Wood Trimmer. - A very useful pattern-shop tool is the wood trimmer, shown in Fig. 106. This machine is much used to cut ends of wood pieces to an exact angle (usually square) with the face or edge of the piece. It consists essentially of a flat table B along the rear edge of which slides a triangular-shaped piece, carrying two knives C and D. The plane of these knives is exactly 90° to the plane of the table. The guide pieces F and G have their faces perpendicular to the plane of the table, and they may be swung around on vertical axes and clamped at any desired angle to the plane of the knives. A piece of work to be cut is held securely by the hand in the angle formed between one of the guides F or G and the table, and the knife cuts off the projecting edge.

Fig. 106. - Wood Trimmer.

The large wheel at the back of the trimmer moves the knives back and forth along the table edge.