M4 Socket Nuts (Hex Drive, Round Body) are manufactured to Trade series (round body socket nut). This page lists the controlling dimensions for the M4 size together 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.
M4 Dimensional Row (Trade series (round body socket nut))
| Thread size | Outer diameter (mm) | Nut height m (mm) | Hex socket s (mm) | Socket depth (mm) | Material | Finish | Note |
|---|---|---|---|---|---|---|---|
| M4 | 8.0 | 8.0 | 4.0 | 3.5 | Alloy steel | Black oxide | Fits 8 mm bore |
Spanner & Drive for M4 Socket Nuts (Hex Drive, Round Body)
The hex socket for M4 Socket Nuts (Hex Drive, Round Body) is shown in the spec table — use the matching Allen / hex key (an ISO 2936 hex key set covers the full range). A T-handle key gives the most feel when you are judging preload by hand; anything repeated across a batch wants a torque-controlled driver instead.
Tightening Torque for M4
| Class 8.8 (dry, ~µ 0.125) | ≈ 2.9 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 5 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 M4
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.
Mating Parts for M4
Pair M4 with the matching M4 bolt or screw, plus a M4 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M4
When the joint preload approaches the proof load of M4 class 8.8, step up to M5 class 8.8 (or move to M4 class 10.9). When the joint is over-specified, M3 often saves weight and cost without losing the safety margin.
Custom manufacturing · Made to drawing
Need socket nuts (hex drive, round body) in a size this table does not list?
This page covers M4 socket nuts (hex drive, round body). 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.
