M24 Grade 12.9 Torque Specification

Torque Values by Surface Condition

Stress area: 352.5 mm² · Proof load: 341,925 N · Clamp load (75%): 256,444 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	1230.9	907.9	10894.4	12551.7
Oiled	0.15	923.2	680.9	8171.0	9414.1
Zinc Plated	0.18	1107.8	817.1	9804.9	11296.5
Waxed	0.1	615.5	454.0	5447.6	6276.4
MoS₂	0.12	738.6	544.8	6537.2	7531.7
Galvanized	0.25	1538.7	1134.9	13618.6	15690.4

Stress area: 384.42 mm² · Proof load: 372,887 N · Clamp load (75%): 279,666 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	1342.4	990.1	11881.2	13688.7
Oiled	0.15	1006.8	742.6	8910.9	10266.5
Zinc Plated	0.18	1208.2	891.1	10693.5	12320.3
Waxed	0.1	671.2	495.1	5940.6	6844.4
MoS₂	0.12	805.4	594.0	7128.4	8212.8
Galvanized	0.25	1678.0	1237.6	14851.6	17110.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 970 MPa × 352.5 mm² = 256,444 N

Step 2 — Torque (dry): T = 0.20 × 0.0240 m × 256,444 N = 1230.9 N·m

Proof stress per ISO 898-1:2013 Table 4. Stress area per ISO 898-1 Annex A. K-factor per VDI 2230.

Socket head cap screws, racing/motorsport, aerospace, maximum strength applications — highest standard grade

• Torque values are for standard hex bolts with ISO metric threads. Socket head cap screws may have different requirements.
• Lubrication reduces required torque significantly — using dry torque values on lubricated bolts risks exceeding yield strength.
• For critical or safety-related applications, always consult the manufacturer's specifications or applicable design standard (e.g., VDI 2230).
• Re-used bolts may have altered friction characteristics. Inspect threads before reuse.

SizeM24

Class12.9

Diameter24 mm

Pitch (coarse)3.0 mm

Tensile1220 MPa

Yield1100 MPa

Proof970 MPa