M24 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 352.5 mm² · Proof load: 109,275 N · Clamp load (75%): 81,956 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	393.4	290.2	3481.9	4011.6
Oiled	0.15	295.0	217.6	2611.0	3008.2
Zinc Plated	0.18	354.1	261.2	3134.1	3610.8
Waxed	0.1	196.7	145.1	1740.9	2005.8
MoS₂	0.12	236.0	174.1	2088.8	2406.5
Galvanized	0.25	491.7	362.7	4351.9	5014.0

Stress area: 384.42 mm² · Proof load: 119,170 N · Clamp load (75%): 89,378 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	429.0	316.4	3797.0	4374.6
Oiled	0.15	321.8	237.3	2848.2	3281.5
Zinc Plated	0.18	386.1	284.8	3417.3	3937.1
Waxed	0.1	214.5	158.2	1898.5	2187.3
MoS₂	0.12	257.4	189.8	2278.2	2624.8
Galvanized	0.25	536.3	395.6	4746.7	5468.8

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 352.5 mm² = 81,956 N

Step 2 — Torque (dry): T = 0.20 × 0.0240 m × 81,956 N = 393.4 N·m

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

Light structural connections, furniture assembly, non-load-bearing joints

• 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

Class4.8

Diameter24 mm

Pitch (coarse)3.0 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa