BS 1127-1:1990

This International Standard specifies the general dimensions of hand-operated and machine-operated screwing dies. These dimensions, established as a function of the thread diameter and pitch, are the following:

• — outside diameter;
• — thickness;
• — cutting portion length;
• — general dimensions of attachment.

It also gives the interchangeability dimensions of hand-operated die stocks.

This International Standard is applicable to screwing dies intended for the manufacture of the following threads:

• — ISO metric threads:
  • — coarse thread, from M1 to M68;
  • — fine thread, from M1 to M56.
• — ISO inch threads:
  • — “Unified coarse” series (UNC), from No.1– 64 to 2 3/4 – 4;
  • — “Unified fine” series (UNF), from No.0– 80 to 1 1/2 – 12.

The dimensional characteristics of circular screwing dies, as a function of thread diameters and pitches, are given in Annex A.

The general dimensions of screwing dies for threads which are not dealt with in this International Standard, and therefore are not recommended, are given for guidance only in Annex B. Annex B is applicable to screwing dies for inch threads of the following types:

B.1 — “British Standard Whitworth” (BSW).

B.2 — “British Standard Fine” (BSF).

B.3 — “British Association” (BA).

All screwing dies are available in two classes, namely

• — non-precision screwing dies;
• — precision screwing dies.

General dimensions of screwing dies and the interchangeability dimensions of die stocks. Applicable to screwing dies intended for the manufacture of: ISO metric coarse threads M1 to M68; ISO metric fine threads M1 to M56; ISO inch (UNC) threads No. 1-64 to 2¾ – 4; ISO inch (UNF) No. 0-80 to 1½ – 12.