When you need Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 030) in the M8 size, the controlling values come from GB/T 819.1 / ISO 7046. This page lists them in one place — pitch, head geometry, tool size and the matching hole.
M8 Dimensional Row (GB/T 819.1 / ISO 7046)
| Size | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Cross recess | Countersink angle (deg) | Reference standard |
|---|---|---|---|---|---|---|---|
| M8 | 1.25 | 50 | 14.5 | 4.0 | PH3 | 90 | ISO 7046 / GB/T 819 |
Spanner & Drive for M8 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 030)
The hex socket for M8 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 030) 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 M8
| Coarse-thread pitch (ISO 724) | 1.25 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 9 mm |
| Tapping drill, coarse thread | 6.8 mm |
Tightening Torque for M8
| Class 8.8 (dry, ~µ 0.125) | ≈ 25 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 35 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 41 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 M8 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 030)
M8 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 030) are commonly specified for machine assembly, general engineering, plant maintenance and OEM equipment.
Mating Parts for M8
For M8, pair with a M8 hex nut (ISO 4032 / DIN 934) and, where used, a M8 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M8
When the joint preload approaches the proof load of M8 class 8.8, step up to M10 class 8.8 (or move to M8 class 10.9). When the joint is over-specified, M6 often saves weight and cost without losing the safety margin.