Head diameter, head height and Phillips driver size for metric machine screws — pan head (DIN 7985), flat head (DIN 963 slotted, DIN 965 Phillips) and oval head (DIN 966).
A metric machine screw is sized by its thread — M4 is 4 mm across — and measured in millimetres. A pan head sits on top, so it is measured under the head; a flat head sits flush in a 90° countersink, so it is measured overall; an oval head is measured from the rim, not counting its dome.
How each head is measured. Letters in the tables: dk head diameter, k head height, f oval dome, n slot width.
| Size | Pitch | Head dia dk max | Head height k max | Phillips |
|---|---|---|---|---|
| M1.6 | 0.35 | 3.2 | 1.42 | PH0 |
| M2 | 0.40 | 4 | 1.72 | PH1 |
| M2.5 | 0.45 | 5 | 2.12 | PH1 |
| M3 | 0.50 | 6 | 2.52 | PH1 |
| M3.5 | 0.60 | 7 | 2.82 | PH2 |
| M4 | 0.70 | 8 | 3.25 | PH2 |
| M5 | 0.80 | 10 | 3.95 | PH2 |
| M6 | 1.00 | 12 | 4.75 | PH3 |
| M8 | 1.25 | 16 | 6.15 | PH4 |
| M10 | 1.50 | 20 | 7.68 | PH4 |
A raised cheese (pan) head; length is under the head. A dash: our two sources differ — give us a call.
| Size | Pitch | Head dia dk max | Head height k max | Phillips |
|---|---|---|---|---|
| M1.6 | 0.35 | 3 | 0.96 | PH0 |
| M2 | 0.40 | 3.8 | 1.2 | PH1 |
| M2.5 | 0.45 | 4.7 | 1.5 | PH1 |
| M3 | 0.50 | 5.6 | 1.65 | PH1 |
| M3.5 | 0.60 | 6.5 | 1.93 | PH2 |
| M4 | 0.70 | 7.5 | 2.2 | PH2 |
| M5 | 0.80 | 9.2 | 2.5 | PH2 |
| M6 | 1.00 | 11 | 3 | PH3 |
| M8 | 1.25 | 14.5 | 4 | PH4 |
| M10 | 1.50 | 18 | 5 | PH4 |
90° countersunk head; length is overall, head included. A dash: our two sources differ — give us a call.
| Size | Pitch | Head dia dk max | Head height k max | Slot width n |
|---|---|---|---|---|
| M1 | 0.25 | 1.9 | 0.6 | 0.25 |
| M1.2 | 0.25 | 2.3 | 0.72 | 0.3 |
| M1.4 | 0.30 | 2.6 | 0.86 | 0.3 |
| M1.6 | 0.35 | 3 | 0.96 | 0.4 |
| M2 | 0.40 | 3.8 | 1.2 | 0.5 |
| M2.5 | 0.45 | 4.7 | 1.5 | 0.6 |
| M3 | 0.50 | 5.6 | 1.65 | 0.8 |
| M4 | 0.70 | 7.5 | 2.2 | 1 |
| M5 | 0.80 | 9.2 | 2.5 | 1.2 |
| M6 | 1.00 | 11 | 3 | 1.6 |
| M8 | 1.25 | 14.5 | 4 | 2 |
| M10 | 1.50 | 18 | 5 | 2.5 |
| M12 | 1.75 | 22 | 6 | 3 |
| M16 | 2.00 | 29 | 8 | 4 |
| M20 | 2.50 | 36 | 10 | 5 |
90° countersunk head; length is overall, head included. A dash: our two sources differ — give us a call.
| Size | Pitch | Head dia dk max | Countersink height k max | Phillips | Dome f approx |
|---|---|---|---|---|---|
| M1.6 | 0.35 | 3 | 0.96 | PH0 | 0.4 |
| M2 | 0.40 | 3.8 | 1.2 | PH1 | 0.5 |
| M2.5 | 0.45 | 4.7 | 1.5 | PH1 | 0.6 |
| M3 | 0.50 | 5.6 | 1.65 | PH1 | 0.75 |
| M3.5 | 0.60 | 6.5 | 1.93 | PH2 | 0.9 |
| M4 | 0.70 | 7.5 | 2.2 | PH2 | 1 |
| M5 | 0.80 | 9.2 | 2.5 | PH2 | 1.25 |
| M6 | 1.00 | 11 | 3 | PH3 | 1.5 |
| M8 | 1.25 | 14.5 | 4 | PH4 | 2 |
| M10 | 1.50 | 18 | 5 | PH4 | 2.5 |
A 90° countersunk head with a raised dome (dome height f, approx., in the last column); length is from the rim — the dome is not counted. A dash: our two sources differ — give us a call.
Good to know
Phillips sizes run PH0 to PH4 — use the size in the table, a smaller bit cams out. Inch machine screws are on the machine screw chart; metric thread pitches on the metric thread pitch chart.
Quick answers
- What size Phillips bit fits an M4 pan head machine screw?
- A PH2 (DIN 7985).
- What Phillips bit goes with each metric pan head screw?
- M1.6 – PH0, M2 – PH1, M2.5 – PH1, M3 – PH1, M3.5 – PH2, M4 – PH2, M5 – PH2, M6 – PH3, M8 – PH4, M10 – PH4.
- How big is the head on an M5 flat head machine screw?
- 9.2 mm across, maximum, 2.5 mm tall (DIN 965 / 963).
- How is a metric flat head machine screw measured?
- Overall, head included — it sits flush in a 90° countersink. A pan head is measured under the head.