46 CFR 160.043-4 - Construction and workmanship.
(a) Blade. The blade shall be not less than 0.095 inch thick at the tang. Shall have a triangular section and sheeps foot point. It shall have a cutting edge approximately 3 1/8 inches in length and shall be approximately 13/16 inch in height at the point. The blade shall be uniformly ground and finished on both sides and sharpened to a uniform and keen edge, and it shall have a common nail nick on one side. Before assembling, the sides of the tang shall be uniformly polished.
(b) Can opener. The can opener shall be not less than 0.072 inch thick at the tang, and 1 11/16 to 1 15/16 inches long overall. It shall be so designed that the cutting action turns the ragged edge down into the can, and shall be mounted at the same end of the knife as the blade and in such a manner that both rectangular and circular cans may be opened with a minimum of effort when the knife is held in the right hand and operated in a clockwise direction around the can. The cutting edge shall be suitably formed to obtain a smooth cutting action. It shall have a common nail nick on one side, and the extreme distal end shall be pointed. It shall be polished on both sides, and before assembling, the side of the tang shall be polished.
(c) Springs. Each spring shall be of a thickness corresponding to the blade it operates, and the back edge and that section of the front edge coming in contact with the end of the tang of the blade shall be polished.
(d) Linings and center. Linings and center shall be not less than 0.022 inch in thickness and shall be polished before assembly.
(e) Bolsters. The bolsters shall be approximately 9/16 inch long by 0.100 inch thick measured at the center line.
(f) Shackle. The shackle shall be of conventional design, not less than 0.120 inch in diameter, and shall extend not less than 3/4 inch from the end of the knife. The shackle shall be attached to the knife by a solid nickel-silver pin not less than 0.080 inch in diameter which shall pass through the shackle and be securely fastened.
(g) Handles. The handles shall be approximately 3 3/4 inches long. They shall be well fitted at the bolsters and fastened to the linings by two solid rivets countersunk on the inside of the linings and smoothly rounded on the outside.
(h) Rivets and pins. Pins holding the handles to the linings shall be of hard brass, not less than 0.048 inch in diameter. Middle and end pins shall be of hard brass not less than 0.095 inch in diameter. The bolster rivet shall be 18 percent nickel-silver not less than 0.095 inch in diameter. All rivets and pins shall have carefully spun heads.
(i) Lanyard. A lanyard 6 feet in length shall be secured to the shackle.
(j) Polishing and oiling. After assembly all outside surfaces shall be buffed, and the metal parts polished uniformly. The working parts shall be cleaned and oiled with a good grade of joint oil.
(k) Workmanship. Workmanship shall be first class in all respects, and jackknives shall be free from defects which may affect their serviceability.