M27 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 459.41 mm² · Proof load: 142,417 N · Clamp load (75%): 106,813 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	576.8	425.4	5105.1	5881.7
Oiled	0.15	432.6	319.1	3828.8	4411.3
Zinc Plated	0.18	519.1	382.9	4594.4	5293.4
Waxed	0.1	288.4	212.7	2552.6	2940.9
MoS₂	0.12	346.1	255.3	3063.2	3529.3
Galvanized	0.25	721.0	531.8	6381.4	7352.2

Stress area: 496.18 mm² · Proof load: 153,816 N · Clamp load (75%): 115,362 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	623.0	459.5	5514.0	6352.9
Oiled	0.15	467.2	344.6	4135.1	4764.1
Zinc Plated	0.18	560.7	413.6	4962.6	5717.6
Waxed	0.1	311.5	229.8	2757.0	3176.4
MoS₂	0.12	373.8	275.7	3308.4	3811.7
Galvanized	0.25	778.7	574.3	6892.1	7940.6

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 459.41 mm² = 106,813 N

Step 2 — Torque (dry): T = 0.20 × 0.0270 m × 106,813 N = 576.8 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.

SizeM27

Class4.8

Diameter27 mm

Pitch (coarse)3.0 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa