AS/NZS 1252:1996 pdf – High-strength steel bolts with associated nuts and washers for structural engineering.
3.1 METHOD OF MANUFACTURE High-strength steel nuts shall be—
(a) hot or cold formed with or without subsequent machining; or
(b) machined from bar stock.
3.2 SHAPE, DIMENSIONS AND FINISH
3.2.1 General The shape of nuts shall be in accordance with Figure 3. 1.
For hot-dip galvanized nuts, the dimensions apply before hot-dip galvanizing (see Clause 3.2.2.2).
3.2.2 Screw threads
3.2.2.1 General The thread form, diameters and associated pitches of nuts shall be those of the ISO coarse pitch series in accordance with AS 1275.
3.2.2.2 Tolerances Hot-dip galvanized nuts shall be tapped oversize in accordance with AS 1214 after galvanizing. The screw threads of uncoated nuts shall be made to tolerance class 6H in accordance with AS 1275.
3.2.3 Chamfering, washer facing and countersinking
3.2.3.1 Chamfering and washer facing Nuts shall have a chamfer of 15 to 30 degrees on both faces, or a chamfer of 15 to 30 degrees on their upper face and a washer face on the bearing surface. The bearing faces shall be smooth and flat. The minimum washer face or chamfer diameter (d,) shall be not less than that given in Figure 3. 1.
3.2.3.2 Countersinking Nuts shall be radiused or countersunk on the bearing face or faces.
The maximum countersink diameter (tia) shall be not greater than the value given in
Figure 3.1.
3.2.4 Squareness and symmetry
3.2.4.1 Squareness of thread to hearing face(s) When determined as shown in
Figure 3.2(a) the bearing face(s) of the nut shall be square, within the values given in
Figure 3.1, to the pitch diameter of the screw thread.
NOTE: A recommended method of checking this feature in conjunction with an appropriate gauge design is described and illustrated in Appendix B.
3.2.4.2 Svinmeirv of hexagon When determined as shown in Figure 3.2(b), the hexagon shall he symmetrical, within the values given in Figure 3. 1, to the pitch diameter of the screw thread.
3.2.5 Finish
3.2.5.1 General High-strength steel nuts shall he cleanly finished, sound and free from defects detrimental for their end use. The surface discontinuities shall be not greater than the limits given in SAE J122a.
3.2.5.2 Suiftice roughness All surfaces of high-strength steel nuts, except screw threads, may be in the as-forged or machined condition. Screw threads shall be machined or have a surface quality equivalent to machining.
3.2.5.3 Sui:face finish Unless otherwise specified, high-strength steel nuts shall be supplied hot-dip galvanized in accordance with AS 1214. Uncoated nuts shall be in the dull black as- heat-treated condition.
3.2.5.4 Coated nuts Nuts may be supplied with either decorative or corrosion-resistant coatings.
AS/NZS 1252:1996 pdf – High-strength steel bolts with associated nuts and washers for structural engineering
