BS 3A 100:1991

Foreword
Committees responsible
1 Scope
2 Material
3 Manufacture
4 Dimensions
5 Runout and lead threads for rolled threads
6 Screw thread form and class of fit
7 Anti-corrosion treatment
8 Identification marking
9 Quality assurance procedure
10 Additional requirements for cold-forged and hot-
      forged steel bolts
Appendix A - Dimensions of unified thread identification
             features on aircraft bolts and nuts
Table 1 - Inspection levels
Table 2 - Surface texture
Table 3 - Geometrical straightness tolerances for bolt
          shanks
Table 4 - Nut squareness tolerances
Table 5 - Maximum depth of defect
Table 6 - Bolt hardness ranges
Table 7 - Alternative identification features for
          hexagonal-headed bolts other than shear bolts
Table 8 - Alternative identification features for
          hexagonal-headed shear bolts
Table 9 - Identification features for mushroom head and
          pan head bolts
Table 10 - Identification feature for nuts
Figure 1 - Geometrical tolerances for bolts
Figure 2 - Geometrical tolerances for nuts
Figure 3 - Nut squareness gauge
Figure 4 - Minimum acceptable standard of grain flow
           (after machining if applicable)
Figure 5 - Ordinary bolts
Figure 6 - Bolts with close tolerance shanks
Figure 7 - Hexagonal-headed shear bolts
Figure 8 - Mushroom head bolts with recess
Figure 9 - Pan head bolts with recess
Figure 10 - Nut

Gives the general requirements for aerospace bolts and free running nuts of tensile strength not exceeding 1249 MPa.