Metric Countersinks | McMaster-Carr

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26 Products

About Countersinks

Choose the right countersink angle, body diameter, and number of flutes for your application.

Drill-Point Countersinks for Screws

Save time by drilling a pilot hole and countersinking in a single step. These countersinks have a small drill point to drill new pilot holes topped with cone-shaped recesses for screw heads.

High-Speed Steel

2 Flutes

These versatile, wear-resistant countersinks cut cleanly in most materials, including plastic, aluminum, and steel.

Number of Flutes—Countersinks with fewer flutes reduce chatter, so you can run them at high speeds. Countersinks with a higher number of flutes remove more material per revolution, leaving a smoother finish and extending tool life.

Manufacturer—We source from trusted manufacturers who vet raw materials for purity and use diamond grinding wheels to machine precise edges. This keeps cutting surfaces smooth and free of microscopic burrs. Because our suppliers clean their wheels more often than other manufacturers, each countersink is consistently ground to create uniform holes every time.

	Dia., mm						Uncoated
	Body	Shank	Drill Tip Dia., mm	For Screw Size	Overall Lg., mm	Shank Type	Mfr.		Each
2 Flutes







				90° Countersink Angle

				6.35	6.35	3.10	M3	44.44	Round	Link Industries	28145A71	000000


				8.20	6.35	4.10	M4	44.44	Round	Link Industries	28145A72	00000
				11.10	7.93	5.10	M5	50.79	Round	Link Industries	28145A73	00000
				12.70	7.93	6.10	M6	50.79	Round	Link Industries	28145A74	00000
				17.45	11.11	8.10	M8	66.66	Round	Link Industries	28145A75	00000
				20.63	12.7	10.10	M10	76.19	Round	Link Industries	28145A76	00000
				25.40	15.87	12.10	M12	76.19	Round	Link Industries	28145A77	00000

Oversized Counterbores

Designed to give screw heads a slightly loose fit, these counterbores are a bit wider than standard sizes. The extra clearance prevents binding and leaves room for a seal or O-ring around the screw head.

High-Speed Steel

Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.

		Pilot			Shank			Uncoated
For Screw Size	Body Dia., mm	Dia., mm	Lg.	Overall Lg.	Dia.	Type	No. of Flutes		Each







			0.5 mm Oversize

			M3	6.0	3.5	0.219"	4 1/2"	3/16"	Round	4	2740A11	000000


			M4	7.5	4.5	0.250"	5"	1/4"	Round	4	2740A12	00000
			M5	9.0	5.5	0.281"	5 5/8"	5/16"	Round	4	2740A13	00000
			M6	10.5	6.5	0.313"	5 5/8"	5/16"	Round	4	2740A14	00000
			M8	13.5	8.5	0.375"	6 1/2"	1/2"	Round	4	2740A15	00000
			M10	16.5	10.5	0.500"	7"	1/2"	Round	4	2740A16	00000
			M12	18.5	12.5	0.500"	7 1/8"	1/2"	Round	4	2740A17	00000
			M14	21.5	14.5	0.563"	7 1/2"	5/8"	Round	4	2740A18	000000
			M16	24.5	16.5	0.625"	7 5/8"	5/8"	Round	4	2740A22	000000
			M20	30.5	20.5	0.750"	8 1/8"	7/8"	Round	4	2740A26	000000

Drill-Point Counterbores

Skip a step when installing screws in metal. With a sharp point on the tip, these counterbores drill a pilot hole topped with a flat recess for the screw head. That's faster and more accurate than switching to a counterbore in between passes with your drill bit.

High-Speed Steel

Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.

			Shank				Uncoated
For Screw Size	Body Dia., mm	Overall Lg.	Dia.	Type	No. of Flutes	Max. Hole Drilling Dp., mm		Each



	M3	5.9	1 1/4"	1/4"	Round	2	6.35	29445A21	000000


	M4	7.5	1 3/8"	1/4"	Round	2	7.54	29445A22	00000
	M5	9.1	1 1/2"	5/16"	Round	2	7.94	29445A23	00000
	M6	10.7	1 9/16"	5/16"	Round	2	9.52	29445A24	00000
	M8	13.4	1 13/16"	7/16"	Round	2	11.11	29445A25	00000
	M10	16.6	2 1/16"	1/2"	Round	2	14.29	29445A26	00000
	M12	18.7	2 7/16"	5/8"	Round	2	15.87	29445A27	00000
	M14	21.8	2 5/8"	5/8"	Round	2	16.67	29445A28	00000
	M16	24.6	2 3/4"	5/8"	Round	2	17.46	29445A29	00000