Figure 86.
Nomenclature of the Sear.—The sear, [Fig. 83], consists of: a, the body; b, the nose; c, the arm; d, screw-hole.
Nomenclature of the Sear-Spring.—The sear-spring, [Fig. 84], consists of: a, the blade; b, upper branch; c, lower branch; d, the stud; e, screw-hole.
Nomenclature of the Swivel.—The mainspring-swivel or stirrup, [Fig. 85], consists of: a, the body; b, the axis; and c, the tumbler-pin hole.
Nomenclature of the Breech-Pin.—[Fig. 86] shows full size of musket-barrel breech-pin. a, plug with threads; b, tenon; c, tang; d, tang-screw hole; e, face.
In sporting guns the tang is often called the “strap,” and is distinguished as long and short. The length varying from two and a half inches as shortest, and five inches as the longest. Sometimes the term “tail” is employed instead of tang or strap. The diameter of the plug is generally one-half, five-eighths, and three-quarters of an inch. The diameter of the pin used in United States muskets and rifles is three-quarters of an inch.
Nomenclature of Screws.—In all the screws, the parts are the stem, the head, the slot and the thread.