On the bench specifying M4 Hex Head Bolt — GB/T 5782 / ISO 4014 (Series 002)? This page gives the controlling dimensions for the M4 size of Hex Head Bolt — GB/T 5782 / ISO 4014 (Series 002) (to GB/T 5782 / ISO 4014).
M4 Dimensional Row (GB/T 5782 / ISO 4014)
| Size | Pitch (mm) | Nominal diameter d (mm) | Length L (mm) | Width across flats s (mm) | Width across corners e (mm) | Head height k (mm) |
|---|---|---|---|---|---|---|
| M4 | 0.7 | 4 | 25 | 7.0 | 7.66 | 2.8 |
Spanner & Drive for M4 Hex Head Bolt — GB/T 5782 / ISO 4014 (Series 002)
M4 Hex Head Bolt — GB/T 5782 / ISO 4014 (Series 002) have a width across flats of 7.0 mm — fit a 7.0 mm open-ended spanner or socket. Use a 6-point socket for tight clearances and to reduce rounding; for repeated assembly choose a torque wrench so the joint preload is repeatable.
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) | ≈ 4.1 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 4.9 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.
Common Applications for M4 Hex Head Bolt — GB/T 5782 / ISO 4014 (Series 002)
M4 Hex Head Bolt — GB/T 5782 / ISO 4014 (Series 002) are commonly specified for precision instruments, small machinery and consumer-electronics enclosures.
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.
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.