Dimensional and assembly data for M4 Hexalobular Socket Countersunk Head Screws, High Head to ISO 14582. Includes head size and width across flats, clearance-hole and tapping-drill diameters, tightening torque per property class, and the sizes to step up or down to when the joint requires it.
M4 Dimensional Row (ISO 14582)
| Size | Pitch P (mm) | a (mm) | b (mm) | Head diameter dk (mm) | csh_diam (mm) | csh_height (mm) | r (mm) | tt (mm) | A2 (mm) | t_mean (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M4 | 0.7 | 1.4 | 20.0 | 10.02 | 9.0 | 3.01 | 0.2 | T20 | 3.95 | 1.6 | 8~40 | ISO 14582 |
Spanner & Drive for M4 Hexalobular Socket Countersunk Head Screws, High Head
Drive geometry for M4 Hexalobular Socket Countersunk Head Screws, High Head 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 Hexalobular Socket Countersunk Head Screws, High Head Weight
A steel M4 hexalobular socket countersunk head screws, high head at the listed 840 mm length weighs approximately 520 g each — about 520 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 Hexalobular Socket Countersunk Head Screws, High Head
- 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.
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 hexalobular socket countersunk head screws, high head in a size this table does not list?
This page covers M4 hexalobular socket countersunk head screws, high head. 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 warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
