BS 939:1977
Superseded
A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
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Specification for engineers\' squares (including cylindrical and block squares)
Hardcopy , PDF
31-10-2007
English
30-09-1977
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Foreword
Cooperating organizations
Specification
Section one. General
1. Scope
2. References
3. Nomenclature and definitions
4. Protection against climatic conditions
Section two. Engineers' try squares
5. Designating size
6. Recommended sizes
7. Material and manufacture
8. General features of design
9. Finish
10. Accuracy
11. Rigidity
12. Marking
Section three. Cylindrical square
13. Designating size
14. Recommended sizes and dimensions
15. Material and manufacture
16. General features of design
17. Finish
18. Accuracy
19. Marking
Section four. Solid form block squares
20. Designating size
21. Recommended sizes and dimensions
22. Material and manufacture
23. General features of design
24. Finish
25. Accuracy
26. Marking
Section five. Open form block squares
27. Designating size
28. Recommended sizes and dimensions
29. Material
30. General features of design
31. Finish
32. Accuracy
33. Marking
Appendices
A. Notes regarding bevelled edges of grade AA
engineers' try squares
B. Notes on the manufacture and testing of squares
Tables
1. Tolerances on straightness of blade edges
2. Tolerances on parallelism of blade edges
3. Tolerances on flatness of working faces of stock
4. Tolerances of parallelism of working faces of stock
5. Tolerances on parallelism of side faces of stock
6. Tolerances on squareness of blade edges to working
faces of stock
7. Tolerances on lateral squareness of blade to base
of stock
8. Recommended sizes and dimensions of cylindrical
squares
9. Tolerances on cylindrical squares
10. Recommended sizes and dimensions of solid form
block squares
11. Tolerances on flatness, parallelism and squareness
of working faces (solid iron block squares)
12. Tolerances on flatness and squareness of front and
back surfaces
13. Recommended sizes and dimensions of open form block
squares
14. Tolerances on flatness, parallelism and squareness
of working faces
15. Tolerances on flatness and squareness of front and
back surfaces
Figures
1. Exaggerated illustration of deviation from
squareness and squareness tolerance
2. Engineers' try squares
3. Squareness of blade edges to working faces of stock
4. Lateral squareness of blade
5. Rigidity
6. Nomenclature for cylindrical squares
7. Nomenclature for solid form block squares
8. Nomenclature for open form block squares
9. Using a bevelled edge
10. Method of testing squareness of block squares
11. Tilting square tester
12. Testing for rigidity
Squares of try-square type in three grades of accuracy: AA, A, B; cylindrical squares in grade AA; solid form block squares in grades AA, A; open form block squares in grades A, B. Nomenclature, designation, sizes, material, manufacture, design, accuracy, marking, protection, testing.
| Committee |
MTE/1
|
| DevelopmentNote |
Supersedes 74/77492 DC and BS 939(1962) (10/2005)
|
| DocumentType |
Standard
|
| Pages |
22
|
| PublisherName |
British Standards Institution
|
| Status |
Superseded
|
| SupersededBy | |
| Supersedes |
| BS 6717-1:1993 | Precast concrete paving blocks Specification for paving blocks |
| BS 7825-2:1996 | Calibration of rubber and plastics test equipment Calibration procedures |
| BS 6808-1:1987 | Coordinate measuring machines Glossary of terms |
| BS 8726-1:2002 | Cylindrical helical springs made from rectangular and square section wire and bar. Guide to calculation and design Compression springs |
| BS 1726-1:2002 | Cylindrical helical springs made from round wire and bar. Guide to methods of specifying, tolerances and testing Compression springs |
| BS 1902-3.11:1983 | Methods of testing refractory materials. General and textural properties Measurement of dimensions and shape of refractory bricks and blocks (methods 1902-311) |
| BS 3322:1981 | Specification for carpenters\' squares and bevels |
| BS 1133-6(1966) : 1966 | PACKAGING CODE - TEMPORARY PROTECTION OF METAL SURFACES AGAINST CORROSION (DURING TRANSPORT AND STORAGE) |
| BS 3643(1963) : LATEST | |
| BS 1134:1961 | Centre-line-average height method for the assessment of surface texture |
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