This page covers M22 Hex Bolts to ISO 4014 / ISO 4017: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (ISO 4014 / ISO 4017 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M22 Dimensional Row (ISO 4014 / ISO 4017)
| Size | Pitch coarse (mm) | Width across flats s (mm) | Width across corners e min (mm) | Head height k nom (mm) | Nominal diameter d (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|---|
| M22 | 2.5 | 34.0 | 37.29 | 14.0 | 22.0 | ISO 4014/4017 | Partial / fully threaded |
Spanner & Drive for M22 Hex Bolts
M22 Hex Bolts have a width across flats of 34.0 mm — fit a 34.0 mm open-ended spanner or socket. A 6-point socket grips all six flats of the 34.0 mm hex and is what to reach for once a fastener has been on and off a few times; a 12-point ring spanner starts rounding a worn head. For repeatable preload, torque rather than feel.
Hole Sizes for M22
| Coarse-thread pitch (ISO 724) | 2.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 24 mm |
| Tapping drill, coarse thread | 19.5 mm |
Tightening Torque for M22
| Class 8.8 (dry, ~µ 0.125) | ≈ 573 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 816 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 954 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M22
| Tensile stress area As (ISO 724) | 303 mm² |
|---|---|
| Proof load, class 8.8 | 182 kN |
| Proof load, class 10.9 | 252 kN |
| Proof load, class 12.9 | 294 kN |
| Min. ultimate tensile load, class 8.8 | 252 kN |
Proof load = tensile stress area × the proof stress Sp of the class, per ISO 898-1 — Sp is a lower figure than the yield stress Rp0.2 and the two are not interchangeable. The stress area is computed from this size's own diameter and pitch, so a fine-pitch designation gives the fine-pitch figure. Design the joint so the working preload stays below the proof load of the class selected.
Installation Tips for M22 Hex Bolts
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- On flanged or serrated variants, do NOT add a separate flat washer — the flange already spreads the load and the washer can defeat the locking serrations.
- At M22 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M22
For M22, pair with a M22 hex nut (ISO 4032 / DIN 934) and, where used, a M22 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
Custom manufacturing · Made to drawing
Need hex bolts in a size this table does not list?
This page covers M22 hex bolts. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
