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M22 bolt size

32 mm wrench
across-flats spanner / socket size for M22

M22 bolt — Heavy structural, bridges, machinery.

Full specification

SystemMetric coarse
Nominal diameter22 mm
Thread pitch2.5 mm
Wrench / spanner (across flats)32 mm
Tap drill19.5 mm
Clearance hole24 mm
Common grade / class8.8
Typical torque450 Nm (331.9 ft·lb)
Closest other-system size~7/8 inch

🔧 Torque unit converter

Pre-filled with the typical torque for M22 (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 M22

Heavy structural, bridges, machinery.

A 19.5 mm tap drill is correct for M22 coarse thread. The standard clearance hole is 24 mm.

M22 is part of the ISO metric coarse thread series, defined in ISO 261. The wrench size 32 mm is measured across the flats of the hex head.

Common applications

M22 bolts are widely used in:

  • Heavy structural, bridges, machinery
  • 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 M22 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 M22?
M22 bolt uses a 32 mm wrench or spanner, measured across the flats of the hex head.
What is the torque for M22?
A typical tightening torque for M22 bolt in 8.8 on dry threads is about 450 Nm (331.9 ft·lb). Always confirm against the manufacturer spec for important joints.
What thread pitch and tap drill does M22 use?
M22 bolt has a thread pitch of 2.5 mm and uses a 19.5 mm tap drill, with a 24 mm clearance hole.
What is M22 used for?
M22 is commonly used in heavy structural, bridges, machinery. It is one of the most popular sizes in its category.
What is the closest imperial size to M22?
The closest imperial size to M22 is approximately ~7/8 inch, though they are not exactly interchangeable.

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