M14 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 115.44 mm² · Proof load: 35,786 N · Clamp load (75%): 26,840 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	75.2	55.5	665.6	766.8
Oiled	0.15	56.4	41.6	499.2	575.1
Zinc Plated	0.18	67.6	49.9	598.3	689.3
Waxed	0.1	37.6	27.7	332.8	383.4
MoS₂	0.12	45.1	33.3	399.2	459.9
Galvanized	0.25	93.9	69.3	831.1	957.5

Stress area: 124.55 mm² · Proof load: 38,610 N · Clamp load (75%): 28,958 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	81.1	59.8	717.8	827.0
Oiled	0.15	60.8	44.8	538.1	620.0
Zinc Plated	0.18	73.0	53.8	646.1	744.4
Waxed	0.1	40.5	29.9	358.5	413.0
MoS₂	0.12	48.6	35.8	430.1	495.6
Galvanized	0.25	101.4	74.8	897.5	1034.0

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 115.44 mm² = 26,840 N

Step 2 — Torque (dry): T = 0.20 × 0.0140 m × 26,840 N = 75.2 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.

SizeM14

Class4.8

Diameter14 mm

Pitch (coarse)2.0 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa