Wubei Zhi (Vol. 34)

Comparative Terminology and Dimensions of the Trigger Mechanism

What is today called the Trigger Hook original: jigou (機鉤) was anciently called the Tooth original: ya (牙). What is today called the Rear Sight original: zhaomen (照門) was anciently called the Compass original: gui (規). What is today called the Housing original: xia (匣) was anciently called the Outer Shell original: guo (郭). What is today called the Trigger Lever original: boji (撥機) was anciently called the Hanging Knife original: xuandao (懸刀). What is today called the Intermediate Sear original: dianji (墊機) had no name in ancient times.

The Mechanism Housing The bronze box that contains the trigger components. is one cun A traditional unit of length often called a "Chinese inch." During the Ming dynasty, 1 cun was approximately 3.2 centimeters. and nine fen A subunit of length equal to 1/10th of a cun, roughly 3.2 millimeters. in length, four fen and a fraction in width, and five fen in height.

The Trigger Hook has a total length of seven fen, and the hook itself has a total height of five fen. The Rear Sight has a total height of nine fen. The String-Notch The "mouth" or opening in the hook that catches the bowstring. is two fen deep and two fen wide.

The Intermediate Sear A piece that sits between the hook and the trigger lever to smooth the release. is one cun and three fen long, four fen wide, and one fen thick.

The diameters for the Housing Pin-hole, the Hook Pin-hole, the Sear Pin-hole, and the Trigger Pin-hole are all one fen and a fraction.

The Trigger Lever is one cun and one fen long, four fen wide, and one fen and a fraction thick.

The Two Axle Pins original: jian (鍵); the transverse bolts that act as pivot points for the internal parts. are nine fen long; their thickness should be sized according to the diameter of the respective holes.