Thread Diameter | Friction Coefficient | Tightening Torque M (Nm) Property Class | |||
---|---|---|---|---|---|
50 | 70 | 80 | Bumax 88 | ||
1/4-20 unc | 1.6 | 3.6 | 7.7 | 10 | 11 |
5/16-18 unc | 1.6 | 7.3 | 16.0 | 21 | 22 |
3/8-16 unc | 1.6 | 13.0 | 28.0 | 37 | 39 |
1/2-13 unc | 1.6 | 31.0 | 66.0 | 89 | 95 |
5/8-11 unc | 1.6 | 61.0 | 131.0 | 175 | 188 |
3/4-10 unc | 1.6 | 108.0 | 231.0 | 308 | 329 |
7/8-9 unc | 1.6 | 172.0 | 369.0 | 493 | 527 |
1-8 unc | 1.6 | 258.0 | 553.0 | 737 | 789 |
The friction values can vary depending on many factors: material pairing, the surface quality (peak to valley heights), the surface treatment and the type of lubrication. Therefore this information is only meant as a guide
Note: Stainless steel fasteners tend to seize whilst being assembled (tightened). The risk of seizing is alleviated by:
Impact wrenches are not recommended for torquing 300 series stainless steel fasteners.
The tightening torques as stated above result in a 90% utilization of the yield strength.
Conversion Factor:
Tensile Strength Comparison Chart | What is loading? |
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Super Duplex 2507 Stainless Steel for Engineering & Manufacturing
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