M16 Grade 9.8 Torque Specification

Torque Values by Surface Condition

Stress area: 156.67 mm² · Proof load: 101,835 N · Clamp load (75%): 76,377 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	244.4	180.3	2163.1	2492.2
Oiled	0.15	183.3	135.2	1622.3	1869.1
Zinc Plated	0.18	220.0	162.3	1947.2	2243.4
Waxed	0.1	122.2	90.1	1081.6	1246.1
MoS₂	0.12	146.6	108.1	1297.5	1494.9
Galvanized	0.25	305.5	225.3	2703.9	3115.2

Stress area: 167.25 mm² · Proof load: 108,712 N · Clamp load (75%): 81,534 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	260.9	192.4	2309.2	2660.4
Oiled	0.15	195.7	144.3	1732.1	1995.6
Zinc Plated	0.18	234.8	173.2	2078.2	2394.3
Waxed	0.1	130.5	96.3	1155.0	1330.7
MoS₂	0.12	156.5	115.4	1385.1	1595.9
Galvanized	0.25	326.1	240.5	2886.2	3325.3

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 650 MPa × 156.67 mm² = 76,377 N

Step 2 — Torque (dry): T = 0.20 × 0.0160 m × 76,377 N = 244.4 N·m

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

Heavy-duty automotive, high-performance machinery (limited availability, mostly M16 and smaller)

• 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

Class9.8

Diameter16 mm

Pitch (coarse)2.0 mm

Tensile900 MPa

Yield720 MPa

Proof650 MPa