M3 Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024) is the m3-thread variant of Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024) manufactured to GB/T 2673 / ISO 14587. This page focuses on the data engineers reach for at the bench: dimensional values for the M3 size, the spanner/drive that fits, and the assembly data you need to install it.
M3 Dimensional Row (GB/T 2673 / ISO 14587)
| Size | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Cross recess | Countersink angle (deg) | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 20 | 5.6 | 1.65 | PH1 | 90 | ISO 7046 / GB/T 819 |
Spanner & Drive for M3 Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024)
The hex socket for M3 Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024) 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 Allen key gives the best feel for setting preload by feel; for production work use a torque-controlled driver.
Hole Sizes for M3
| Coarse-thread pitch (ISO 724) | 0.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 3.4 mm |
| Tapping drill, coarse thread | 2.5 mm |
Tightening Torque for M3
| Class 8.8 (dry, ~µ 0.125) | ≈ 1.3 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 1.8 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 2.1 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 M3 Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024)
M3 Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024) are commonly specified for electronics, PCB hardware, optical mounts and small-scale machinery.
Installation Tips for M3 Torx Recessed Countersunk Screw — GB/T 2673 / ISO 14587 (Series 024)
- Use a quality Allen key fully seated in the socket — partial engagement is the most common cause of stripped sockets at this size.
- For countersunk and button-head variants, chamfer the through-hole to seat the head flush without preloading the head/shank fillet.
- At M3 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 M3
When the joint preload approaches the proof load of M3 class 8.8, step up to M4 class 8.8 (or move to M3 class 10.9). When the joint is over-specified, M2 often saves weight and cost without losing the safety margin.