This page covers M12 Phillips Countersunk Machine Screw to GB/T 819.1 / ISO 7046: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (GB/T 819.1 / ISO 7046 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M12 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 |
|---|---|---|---|---|---|---|---|
| M12 | 1.75 | 80 | 22.0 | 6.0 | PH4 | 90 | ISO 7046 / GB/T 819 |
Spanner & Drive for M12 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 029)
The hex socket for M12 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 029) 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 M12
| Coarse-thread pitch (ISO 724) | 1.75 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 13.5 mm |
| Tapping drill, coarse thread | 10.2 mm |
Tightening Torque for M12
| Class 8.8 (dry, ~µ 0.125) | ≈ 85 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 120 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 145 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 M12
| Tensile stress area As (ISO 898-1) | 84.3 mm² |
|---|---|
| Proof load, class 8.8 | 49 kN |
| Proof load, class 10.9 | 70 kN |
| Proof load, class 12.9 | 82 kN |
| Min. ultimate tensile, class 8.8 | 67 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
M12 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 029) Weight
A steel M12 phillips countersunk machine screw at the listed 80 mm length weighs approximately 239 g each — about 239 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.
Common Applications for M12 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 029)
M12 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 029) are commonly specified for heavier machine assembly and equipment mounting.
Installation Tips for M12 Phillips Countersunk Machine Screw — GB/T 819.1 / ISO 7046 (Series 029)
- 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.
Mating Parts for M12
For M12, pair with a M12 hex nut (ISO 4032 / DIN 934) and, where used, a M12 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.