Dimensional data for M42 Hex Nuts, Grade C to ISO 4034, with the drive and the installation notes for this type.
Values are taken from the governing standard rather than from a general machine-thread table, because this type is not selected on one.
M42 Dimensional Row (ISO 4034)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Nut height m (mm) | Product grade | Reference standard |
|---|---|---|---|---|---|---|
| M42 | 4.5 | 65.0 | 71.3 | 34.0 | Grade C | ISO 4034 / DIN 555 |
Spanner & Drive for M42 Hex Nuts, Grade C
M42 Hex Nuts, Grade C have a width across flats of 65.0 mm — fit a 65.0 mm open-ended spanner or socket. A 6-point socket grips all six flats of the 65.0 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.
Tightening Torque for M42
| Class 8.8 (dry, ~µ 0.125) | ≈ Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 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 M42
Nuts are graded to ISO 898-2 by the proof load the nut itself will hold (classes 04, 05, 5, 6, 8, 10 and 12), not by the 8.8 / 10.9 / 12.9 scale used for bolts. A class-8 nut is the correct mate for a class-8.8 bolt, and the joint is designed on the bolt, so no bolt-tension figure is quoted here.
Installation Tips for M42 Hex Nuts, Grade C
- 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 M42 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 M42
Pair M42 with the matching M42 bolt or screw, plus a M42 flat washer where required to distribute load on softer materials.
Custom manufacturing · Made to drawing
Need hex nuts, grade c in a size this table does not list?
This page covers M42 hex nuts, grade c. Height and across-flats are the two most often changed — a thinner nut for clearance, a larger hex for a tool that is already on the line. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
