M16 Grade 12.9 Torque Specification

Torque Values by Surface Condition

Stress area: 156.67 mm² · Proof load: 151,970 N · Clamp load (75%): 113,977 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	364.7	269.0	3227.9	3718.9
Oiled	0.15	273.5	201.7	2420.7	2788.9
Zinc Plated	0.18	328.3	242.1	2905.7	3347.7
Waxed	0.1	182.4	134.5	1614.4	1860.0
MoS₂	0.12	218.8	161.4	1936.5	2231.1
Galvanized	0.25	455.9	336.3	4035.1	4648.9

Stress area: 167.25 mm² · Proof load: 162,232 N · Clamp load (75%): 121,674 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	389.4	287.2	3446.5	3970.8
Oiled	0.15	292.0	215.4	2584.4	2977.6
Zinc Plated	0.18	350.4	258.4	3101.3	3573.1
Waxed	0.1	194.7	143.6	1723.2	1985.4
MoS₂	0.12	233.6	172.3	2067.5	2382.1
Galvanized	0.25	486.7	359.0	4307.7	4963.0

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 970 MPa × 156.67 mm² = 113,977 N

Step 2 — Torque (dry): T = 0.20 × 0.0160 m × 113,977 N = 364.7 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.

SizeM16

Class12.9

Diameter16 mm

Pitch (coarse)2.0 mm

Tensile1220 MPa

Yield1100 MPa

Proof970 MPa