M4 is one of the standard coarse-thread sizes for pin-in-hex tamper-resistant socket screws under ISO 4762. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.
M4 Dimensional Row (ISO 4762)
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Socket size s (mm) | Security key | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M4 | 0.7 | 7.0 | 4.0 | 3.0 | PH3 | 8~40 | ISO 4762 |
Spanner & Drive for M4 Pin-in-Hex Tamper-Resistant Socket Screws
Drive geometry for M4 Pin-in-Hex Tamper-Resistant Socket Screws is given by the row above; match the tool to the listed values.
Hole Sizes for M4
| Coarse-thread pitch (ISO 724) | 0.7 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 4.5 mm |
| Tapping drill, coarse thread | 3.3 mm |
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
| Tensile stress area As (ISO 724) | 8.8 mm² |
|---|---|
| Proof load, class 8.8 | 5.1 kN |
| Proof load, class 12.9 | 8.5 kN |
| Min. ultimate tensile load, class 8.8 | 7 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.
M4 Pin-in-Hex Tamper-Resistant Socket Screws Weight
A steel M4 pin-in-hex tamper-resistant socket screws at the listed 840 mm length weighs approximately 254 g each — about 254 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³).
Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Installation Tips for M4 Pin-in-Hex Tamper-Resistant Socket Screws
- At M4 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
Mating Parts for M4
For M4, pair with a M4 hex nut (ISO 4032 / DIN 934) and, where used, a M4 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
Custom manufacturing · Made to drawing
Need pin-in-hex tamper-resistant socket screws in a size this table does not list?
This page covers M4 pin-in-hex tamper-resistant socket screws. Lengths and thread lengths outside the standard table are the commonest request, followed by a drive the standard does not offer and a head marked with your own part number. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
