BS 5317:1976

Foreword
Cooperating organizations
Specification
Section one. General
1. Scope
2. References
3. Definitions
Section two. Length bars
4. Description and use: general design
5. Material
6. Hardening and stabilizing
7. Finish
8. Accuracy
9. Connecting screws for grade 1 and grade 2
10. Marking and essential particulars
11. Case
12. Protection against climatic conditions
Section three. Accessories
13. Material
14. Method of attachment
15. Base
16. Large radiused jaw
17. Small plane-faced jaw
18. Spherical end piece
19. Screws
20. Case
21. Protection against climatic conditions
Appendix
A. Interchangeability with bars to BS 1790: 1961
Tables
1. Tolerances on reference grade length bars
2. Tolerances on calibration grade length bars
3. Tolerances on grade 1 length bars
4. Tolerances on grade 2 length bars
Figures
1. Indication of Airy positions and axis
2. Exaggerated illustration of flatness tolerance
3. Exaggerated illustration of parallelism tolerance
4. Exaggerated illustration of squareness tolerance
5. Reference or calibration grade length bar
6. Grade 1 or Grade 2 length bar
7. Threaded connection for length bars
8. Assembly of accessories
9. Base
10. Large radiused jaw
11. Centrality of radius to thickness
12. Small plane-faced jaw
13. Spherical end piece

Cylindrical length bars up to 1200 mm. Accuracy standards for 4 grades, reference, calibration, 1 and 2, and details of screwed connections. Essential features of design and accuracy for accessories commonly used with Grade 2 bars.

This British Standard relates to length bars (end standards) of the cylindrical type having flat, parallel end faces finished by lapping in metric sizes up to 1 200 mm.

NOTE If longer bars are required they should be uniform in diameter and straight overall to the limits laid down in 8.1 and 8.2; tolerances for flatness and parallelism of faces should be proportionate to those specified in the appropriate Table 1 to Table 4 and their lengths should comply with the requirements of 8.4.2.

Provision is made for two designs of length bar, one with complete plane faces and the other with annular faces surrounding an internally threaded hole at one end or both ends of the bar.

Section 2 provides for length bars in four grades of accuracy, namely reference, calibration, grade 1 and grade 2. It gives general dimensions, tolerances on length and requirements for flatness, parallelism and squareness of faces for all grades of bars.

Manufacturers supply single length bars or sets of selected sizes.

Section 3 relates to the essential features of design and accuracy of accessories for use with grade 1 or grade 2 bars.

Appendix A deals with interchangeability between these bars and bars made in accordance with BS 1790.