Every number, traced to the standard it came from.
Calculators and drawn-to-scale geometry for bolted joints, each result shown with its assumptions and its source.
- Thread
- M10 × 1.5
- Class
- 10.9
- Nut factor K
- 0.20 dry
- Target
- 65 % of Fp
- Torque T
- 62.6N·m
- Preload Fi
- 31.3kN
- Proof load Fp
- 48.1kN
Within proof load, 65 %
ISO 898-1:2013, Table 5: 48100 N
Calculated As·Sp: 48131 N (+0.07 %)
- source: As and Sp, ISO 898-1:2013
- assumed: K = 0.20, assumed
- input: 65 % of proof load
- excluded: Not hot-dip galvanized or structural
- formula: T = K·Fi·d
How values are sourced
Assumptions beside the result
Nut factor, lubrication and target preload, beside every torque figure.
The equation is never hidden
The formula as implemented, each symbol and unit, and a worked example.
Sources cited by edition
ISO 898-1:2013, not ISO 898-1. A revised standard means a revision row.
- Calculator
Preload and tightening torque
Preload and tightening torque for an ISO metric bolt, from its thread, property class, nut factor and target fraction of proof load.
Cites ISO 898-1:2013ISO 68-1:2023ISO 261:1998ISO 262:2023
Rev E, 2026-09-26
- Visualizer
Thread geometry and the stress area
The ISO 68-1 basic profile of the selected metric thread, drawn to scale, with d, d2, d1, d3 and the pitch dimensioned, and the tensile stress area As shown as the circle of equal area.
Cites ISO 68-1:2023ISO 724:2023ISO 898-1:2013
Rev A, 2026-09-26
- Visualizer
Preload sensitivity to the nut factor
The preload a calculated tightening torque actually gives when the real nut factor differs from the one assumed, against proof load and minimum yield.
Cites ISO 898-1:2013
Rev B, 2026-10-02
Recently revised
Each change is a revision row, never a silent edit.
- Rev B2026-10-02Preload sensitivity to the nut factorAdded the achieved preload range, the ±25 % band on one preload axis with the nominal Fi, proof load and minimum yield marked
- Rev E2026-09-26Preload and tightening torqueAdded the thread-geometry visualizer below the result, verified separately
- Rev A2026-09-26Thread geometry and the stress areaInitial issue