Metric Threads - Socket Head Cap Screws: Tap and Drill Sizes, Counterbore and Countersink Dimensions, Clearance Diameters, and Bolt Torque Specifications

Tap and Drill Sizes

No	Screw Diameter (mm)	Tap Size	Drill Size (mm)
1	M2	M2 X 0.4	1.6
2	M3	M3 X 0.5	2.5
3	M4	M4 X 0.7	3.3
4	M5	M5 X 0.8	4.2
5	M6	M6 X 1	5
6	M8	M8 X 1.25	6.8
7	M10	M10 X 1.5	8.5
8	M12	M12 X 1.75	10.2
9	M14	M14 X 2	12
10	M16	M16 X 2	14
11	M20	M20 X 2.5	17.5
12	M24	M24 X 3	37.5

Counterbore and Countersink Dimensions and Clearance Diameters

No	Screw Diameter (mm)	Counterbore Diameter (mm)	Counterbore Depth (mm)	Countersink Diameter (mm)	Clearance Diameter Normal Fit (mm)	Clearance Diameter Close Fit (mm)
1	M2	4.4	2	2.6	2.4	2.2
2	M3	6.5	3	3.6	3.7	3.4
3	M4	8.25	4	4.7	4.8	4.4
4	M5	9.75	5	5.7	5.8	5.4
5	M6	11.2	6	6.8	6.8	6.4
6	M8	14.5	8	9.2	8.8	8.4
7	M10	17.5	10	11.2	10.8	10.5
8	M12	19.5	12	14.2	13	12.5
9	M14	22.5	14	16.2	15	14.5
10	M16	25.5	16	18.2	17	16.5
11	M20	31.5	20	22.4	21	20.5
12	M24	37.5	24	26.4	25	24.5

Bolt Torque

No	Screw Diameter (mm)	Bolt Torque Nm (Dry)	Bolt Torque Nm (Lubed)
1	M2
2	M3
3	M4
4	M5	10.3	7.7
5	M6	17.6	13.1
6	M8	42.6	32.1
7	M10	84	64
8	M12	146	110
9	M14	235	176
10	M16	365	274
11	M20	712	534
12	M24	1231	923