95. Brass Tool.—[Fig. 77]. Forging, hardening, and tempering. Material: 6 to 8 inches of 1⁄2 × 1-inch tool steel.
Starting about 3⁄4 inch from one end, draw to a uniform taper on both sides and on one edge only, so that the metal is 1⁄4 inch thick and 1⁄2 inch wide at the end. The lower or beveled edge also should be drawn thinner than the upper to provide the necessary clearance amounting to about 5 degrees on each side, as shown in the sectional view. The end should be cut off at an angle of 70 degrees and ground semicircular in form with the necessary clearance.
Heat about 2 inches of this end and harden in the manner described for the cold chisel, but in this case the color for tempering is a very pale yellow.
96. Cutting-off or Parting Tool.—[Fig. 78]. Fullering, forging, hardening, and tempering. Material: 7 inches of 1⁄2 × 1-inch tool steel.
Fig. 78.—Cutting-off or Parting Tool.
With a top fuller form a depression across one side 5⁄8 inch from the end, fullering the metal to 3⁄16 inch thick. Draw this end down to 1 × 3⁄16 inch. The thickness of the metal where it was fullered should also be decreased to 1⁄8 inch, gradually increasing to 3⁄16 inch at the end, taking extreme care to have sufficient clearance from front to back and from top to bottom. The cutting edge is generally allowed to project about 1⁄8 inch above the stock; the end is trimmed off at an angle of 75 to 80 degrees and ground, as shown in [Fig. 78], after which it is hardened and tempered to a pale yellow.
97. Heavy Boring Tool.—[Fig. 79]. Drawing, bending, hardening, and tempering. Material: 7 inches of 1⁄2 × 1-inch tool steel.
Fig. 79.—Heavy Boring Tool.