標準號：BS 949-2-1992
中文標準名稱：絲錐.統一磨制螺紋絲錐規范:制造公差
英文標準名稱：Screwing taps - Specification for unified ground thread taps - Manufacturing tolerances
標準類型：J41
發布日期：1992/12/15 12:00:00
實施日期：1992/12/15 12:00:00
中國標準分類號：J41
國際標準分類號：25.100.50
適用范圍：This Part of BS 949 specifies dimensions and tolerances for screwing taps for the following threads: a) Unified (ISO inch) general-purpose screw threads, coarse thread series (UNC), from no. 1 to no. 12 and from 1/4 in to 4 in diameter in accordance with BS 1580 : Parts 1 & 2 : 1962 and BS 1580 : Part 3 : 1965; b) Unified (ISO inch) general-purpose screw threads, fine thread series (UNF), from no. 0 to no. 12 and from 1/4 in to 3/2 in diameter also in accordance with BS 1580 : Parts 1 & 2 : 1962 and BS 1580 : Part 3 : 1965; c) in annex C, British Standard Whitworth (BSW) threads from 1/8 in to 4 in diameter and British Standard Fine (BSF) threads from 3/16 in to 3 in diameter in accordance with BS 84 : 1956; d) also in annex C, British Association (BA) threads from no. 14 to no. 0 in accordance with BS 93 : 1951. NOTE 1. Annex A provides information from which may be calculated the dimensions and tolerances of taps for all Unified threads, including the extra fine thread series (UNEF) and the constant-pitch series (UN). NOTE 2. Annex B gives an example of a calculation of the dimensions of the threaded portion of a tap.