M4 Low Cap (Acorn) Nuts are manufactured to DIN 917. 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 (DIN 917)
| Size | Pitch P (mm) | g2 (mm) | h (mm) | r (mm) | Width across flats s (mm) | t (mm) | w (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|
| M4 | 0.7 | 1.05 | 5.5 | 8 | 7 | 4.16 | 1 | DIN 917 |
Spanner & Drive for M4 Low Cap (Acorn) Nuts
Drive geometry for M4 Low Cap (Acorn) Nuts is given by the row above; match the tool to the listed values.
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 low cap (acorn) nuts in a size this table does not list?
This page covers M4 low cap (acorn) nuts. Thread size is the obvious variable and rarely the interesting one — height for clearance, across-flats for the tool already in the cell, and the locking feature for the vibration actually present. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
