BS 1104:1957

Co-operating organizations
Foreword
Section 1 - Specification
1 Scope
2 Definitions
3 Basic and design forms of thread
4 Nominal sizes
5 Basic diameters
6 Standard series
7 Classes of threads
8 Clearances, allowances, tolerances and limiting
   dimensions
9 Length of engagement
10 Chamfers
11 Special diameters and pitches
12 Designations
Section 2 - Gauging of Acme screw threads
13 Gauges for screws
14 Gauges for nuts
15 Concentricity
16 Lengths of GO screw gauges
17 Tolerances for gauges
18 Gauge limits for the standard series of general
   purpose Acme threads
Appendix A
Appendix B - Effect of pitch and angle errors on
             effective diameter

Defines Acme thread; tables of basic sizes, limits and tolerances for standard series of single start threads ¼ in to 5 in diameter. Agrees with ASA B1.5:1952 except for pitches associated with diameters ⅜ in, $9G in, 1 in, 1¼ in and 1½ in. 2G, 3G and 4G fits in the American standard included, together with finer class, 5G. Tables of effective diameter tolerances for extended range of diameter/pitch combinations are provided. From these and related tables limiting dimensions for any special diameter/pitch combination for single or multi-start Acme thread can be calculated.

This British Standard recommends a Standard Series of diameters and associated pitches for General Purpose Acme form screw threads, for the nominal size range ¼ in. to 5 in. and specifies the limiting dimensions, tolerances and allowances for four classes of thread.

Information is also provided whereby the limiting dimensions for any other screw thread of Acme form may be determined, but the use of these special diameter/pitch combinations should be avoided wherever possible.

Recommendations are given in Section 2 regarding the types and dimensions of gauges to be used.