What size wrench or spanner fits M27?

M27 bolt uses a 41 mm wrench or spanner, measured across the flats of the hex head.

What is the torque for M27?

A typical tightening torque for M27 bolt in 8.8 on dry threads is about 750 Nm (553.2 ft·lb). Always confirm against the manufacturer spec for important joints.

What thread pitch and tap drill does M27 use?

M27 bolt has a thread pitch of 3.0 mm and uses a 24 mm tap drill, with a 30 mm clearance hole.

What is M27 used for?

M27 is commonly used in heavy structural, industrial, marine. It is one of the most popular sizes in its category.

What is the closest imperial size to M27?

The closest imperial size to M27 is approximately ~1-1/8 inch, though they are not exactly interchangeable.

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M27 bolt size

41 mm wrench

across-flats spanner / socket size for M27

M27 bolt — Heavy structural, industrial, marine.

Full specification

System	Metric coarse
Nominal diameter	27 mm
Thread pitch	3.0 mm
Wrench / spanner (across flats)	41 mm
Tap drill	24 mm
Clearance hole	30 mm
Common grade / class	8.8
Typical torque	750 Nm (553.2 ft·lb)
Closest other-system size	~1-1/8 inch

🔧 Torque unit converter

Newton-metres (Nm) Foot-pounds (ft·lb) Inch-pounds (in·lb)

Pre-filled with the typical torque for M27 (8.8, dry). Edit any field to convert.

⚠️ Torque values here are general references for 8.8 on clean, dry threads. Lubrication, coatings, and the joint material change the figure significantly. For structural, automotive, or safety-critical work, always use the torque specified by the manufacturer or engineer.

About M27

Heavy structural, industrial, marine.

A 24 mm tap drill is correct for M27 coarse thread. The standard clearance hole is 30 mm.

M27 is part of the ISO metric coarse thread series, defined in ISO 261. The wrench size 41 mm is measured across the flats of the hex head.

Common applications

M27 bolts are widely used in:

Heavy structural, industrial, marine
General machinery and equipment assembly
Automotive components and repairs
Structural connections (when specified by engineer)
Furniture and fixture assembly

Material and grade information

The typical grade for M27 is 8.8. This indicates:

Property class 8.8: Medium carbon steel, quenched and tempered
Tensile strength: 800 MPa minimum
Yield strength: 640 MPa minimum (0.2% proof stress)
Common coatings: Zinc plated, hot-dip galvanized, or plain

Frequently asked questions

What size wrench or spanner fits M27?: M27 bolt uses a 41 mm wrench or spanner, measured across the flats of the hex head.
What is the torque for M27?: A typical tightening torque for M27 bolt in 8.8 on dry threads is about 750 Nm (553.2 ft·lb). Always confirm against the manufacturer spec for important joints.
What thread pitch and tap drill does M27 use?: M27 bolt has a thread pitch of 3.0 mm and uses a 24 mm tap drill, with a 30 mm clearance hole.
What is M27 used for?: M27 is commonly used in heavy structural, industrial, marine. It is one of the most popular sizes in its category.
What is the closest imperial size to M27?: The closest imperial size to M27 is approximately ~1-1/8 inch, though they are not exactly interchangeable.