Calculation References

1. Budynas and Nisbett, Shigley's Mechanical Engineering Design. Torque-tension relationships using both the simplified nut-factor form, T = K D F, and the detailed screw-thread plus bearing-friction model.
2. Machinery's Handbook, 29th Edition, Industrial Press. Fastener torque and tension discussion, including yield clamping force, page 1530.
3. Fastenal, Torque-Tension Relationship for A307A, Grade 5, 8 and 9 Bolts, Rev. 3-6-09, page 1. Used for advisory torque-table conventions, the note that clamp load is 75% of proof load, and the KDF comparison method.

Proof And Yield Basis

• ASTM A307 Grade A: 33 ksi proof stress, 60 ksi tensile strength, and 36 ksi yield strength from Machinery's Handbook, 29th Edition, grade identification and mechanical properties table, page 1534.
• SAE J429 Grade 5: 85 ksi proof stress for 1/4-1 in fasteners from Machinery's Handbook, 29th Edition, grade identification and mechanical properties table, page 1534; cross-checked against Portland Bolt, SAE J429 Mechanical Properties table.
• SAE J429 Grade 8: 120 ksi proof stress from Machinery's Handbook, 29th Edition, grade identification and mechanical properties table, page 1534; cross-checked against Portland Bolt, SAE J429 Mechanical Properties table.
• Grade 9: 140 ksi basis inferred from the Fastenal page 1 FNL Grade 9 clamp-load columns and the chart note that clamp load is 75% of proof load.
• ASTM A574 SHCS: 140 ksi proof stress through 1/2 in and 135 ksi above 1/2 in from STS Industrial, ASTM A574 Mechanical Requirements table.
• 18-8 SS: ASTM F593 Group 1 cold-worked fastener yield basis, 65 ksi for CW1 and 45 ksi for CW2, from Portland Bolt, ASTM F593 Mechanical Properties / Condition table. MatWeb cross-check: 304 / 18-8 cold-finished and annealed bar, Mechanical Properties table.
• 316 SS: ASTM F593 Group 2 cold-worked fastener yield basis, 65 ksi for CW1 and 45 ksi for CW2, from Portland Bolt, ASTM F593 Mechanical Properties / Condition table. MatWeb cross-check: 316 annealed and cold-drawn bar, Mechanical Properties table.
• A286 SS: ASTM A453 Grade 660 Class D, 105 ksi yield basis from Boltport, ASTM A453 Grade 660 Mechanical Properties table.
• A286 SS material cross-check: MatWeb 660 Stainless Steel A286 cold drawn, aged wire, Mechanical Properties table. The calculator does not use this high wire value because it is condition-specific and not a general bolting proof-load value.
• Titanium Grade 2: 40 ksi yield basis from MatWeb, Titanium Grade 2, Mechanical Properties table.
• Titanium Grade 5: 120 ksi yield basis from MatWeb, Titanium Ti-6Al-4V Grade 5 Annealed Bar, Mechanical Properties table.
• Metric property classes 8.8, 10.9, and 12.9: 600, 830, and 970 MPa proof-load stresses from AFT Fasteners, metric bolt strength chart.