Drill sizes for self-tapping screws

On this page you find the correct drill sizes for using self-tapping screws in steel, in brass and in aluminium. For using the correct drill it's also important to measure the thickness of the material you're working with. Use always the correct drill diameter (all measures are in milimeters)


(mm)	(mm)	(mm)	(mm)
		steel brass	alum.
2,9	0,00 - 0,56	2,20	-
	0,56 - 0,75	2,25	2,20
	0,75 - 1,38	2,40	2,20
	1,38 - 1,75	2,50	2,25
	1,75 - 2,50	2,60	2,40
3,5	0,00 - 0,56	2,60	-
	0,56 - 0,75	2,70	-
	0,75 - 0,88	2,70	2,65
	1,00 - 1,25	2,80	2,65
	1,38 - 1,75	2,90	2,75
	1,75 - 2,50	3,00	2,85
	2,50 - 3,00	3,20	3,00
	3,00 - 6,00	-	3,00


(mm)	(mm)	(mm)	(mm)
		steel brass	alum.
4,2	0,50 - 0,63	3,20	-
	0,63 - 0,88	3,20	2,95
	0,88 - 1,13	3,20	3,00
	1,13 - 1,38	3,30	3,20
	1,38 - 2,50	3,50	3,50
	2,50 - 3,00	3,80	3,70
	3,00 - 3,50	3,90	3,80
	3,50 - 10,0	-	3,90
4,8	0,50 - 0,75	3,70	-
	0,75 - 1,13	3,70	3,70
	1,13 - 1,38	3,90	3,70
	1,38 - 1,75	3,90	3,70
	1,75 - 2,50	4,00	3,80
	2,50 - 3,00	4,10	3,80
	3,00 - 3,50	4,30	3,90
	3,50 - 4,00	4,40	3,90
5,5	0,00 - 1,13	4,20	-
	1,13 - 1,50	4,30	4,10
	1,50 - 1,75	4,50	4,20
	1,75 - 2,25	4,60	4,40
	2,25 - 3,00	4,70	4,60
	3,00 - 3,50	5,00	4,60
	3,50 - 4,00	5,00	4,80
	4,00 - 4,75	5,10	4,80
	4,75 - 10,0	-	4,90

A self-tapping screw is a screw that can tap its own hole as it is driven into the material. Some self-tapping screws are also self-drilling, which means that, in addition to the tap-like flute in the leading threads, there is also a preliminary drill-like fluted tip that looks much like the tip of a center drill. These screws combine a thrilling-like action and the fastener installation itself into only one driving motion (instead of separate drilling, tapping, and installing motions); they are thus very efficient in a variety of hard-substrate applications, from assembly lines to roofing. Read all about self-tapping screws, self-drilling screws, sheet metal screws - also called P-K screws and more on: Wikipedia

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