Hobson tightening torque chart
Class 10.9 Hex Bolt Torque Chart: Metric Coarse, M3 to M64
Hobson's one-page table for class 10.9 metric coarse hex bolts. For each size from M3 to M64 it gives the pitch, stress and core area, tensile, proof and shear load, and the recommended tightening torque for plain, zinc plated and hot dip galvanised (HDG) bolts.
What this covers
- Tensile, proof and shear load
- Recommended tightening torque: plain, zinc, HDG
Key things to remember
The essentials from this document in plain words. Check the full document before you rely on a figure.
- Covers sizes M3 to M64; M42 to M64 figures are marked as extrapolated.
- Recommended torque, plain / zinc / HDG: M10 62.6 / 43.8 / 131.4Nm; M12 109.2 / 76.4 / 229.2Nm; M16 271.0 / 189.7 / 569.2Nm; M20 528.7 / 370.1 / 1,110.3Nm.
- Loads for M12: tensile 87.7kN, proof 70.0kN, shear 47.5kN. M20: 254.8kN, 203.4kN and 140.4kN. These are strength figures, not working loads.
- Conditions: a guide only, for the first tightening of a single assembly on its own, using a k factor of 0.2 for plain threads (burr-free, lightly oiled), 0.14 for zinc plated and 0.42 for hot dip galvanised.
- The document states these figures are not to be used for structural fasteners or structural applications.
Who it helps: Fitters and engineers tightening high tensile class 10.9 bolts.
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This document is published by Hobson Engineering, who supply this range to us. We show it here in full so you can read it next to the product; the summary above is ours. Read it on this page or download the PDF. For the most current version, ask us.