Metric Tap & Drill Chart

The twist drill bit was invented by Steven A. Morse of East Bridgewater, MA, in 1861. He received U.S. Patent 38,119 for his invention on April 7, 1863. The original method of manufacture was to cut two grooves in opposite sides of a round bar, then to twist the bar to produce the helical flutes. This gave the tool its name.

Nowadays, the drill bit is usually made by rotating the bar while moving it past a grinding wheel to cut the flutes in the same manner as cutting helical gears. Tools recognizable as twist drill bits are currently produced in diameters covering a range from 0.05 mm (0.002") to 100 mm (4"). Lengths up to about 1000 mm (39") are available for use in powered hand tools.

The geometry and sharpening of the cutting edges is crucial to the performance of the bit. Users often throw away small bits that become blunt, and replace them with new bits, because they are inexpensive and sharpening them well is difficult. For larger bits, special grinding jigs are available. A special tool grinder is available for sharpening or reshaping cutting surfaces on twist drills to optimize the drill for a particular material. -Wikipedia

Standard metric tap & drill size chart

Coarse Thread			Fine Thread
Thread Size	Tap Drill Diameter (mm)		Thread Size	Tap Drill Diameter (mm)
M1x0.25	0.75		M4x0.35	3.6
M1.1x0.25	0.85		M4x0.5	3.5
M1.2x0.25	0.95		M5x0.5	4.5
M1.4x0.3	1.1		M6x.5	5.5
M1.6x0.35	1.25		M6x.75	5.25
M1.7x0.35	1.3		M7x.75	6.25
M1.8x0.35	1.45		M8x.5	7
M2x0.4	1.6		M8x.75	7.25
M2.2x0.45	1.75		M8x1	7.5
M2.5x0.45	2.05		M9x1	8
M3x0.5	2.5		M10x0.75	9.25
M3.5x0.6	2.9		M10x1	9
M4x0.7	3.3		M10x1.25	8.8
M4.5x0.75	3.7		M11x1	10
M5x0.8	4.2		M12x.75	11.25
M6x1	5		M12x1	11
M7x1	6		M12x1.5	10.5
M8x1.25	6.8		M14x1	13
M9x1.25	7.8		M14x1.25	12.8
M10x1.5	8.5		M14x1.5	12.5
M11x1.5	9.5		M16x1	15
M12x1.75	10.2		M16x1.5	14.5
M14x2	12		M18x1	17
M16x2	14		M18x2	16
M18x2.5	15.5		M20x1	19
M20x2.5	17.5		M20x1.5	18.5
M22x2.5	19.5		M20x2	18
M24x3	21		M22x1	21
M27x3	24		M22x1.5	20.5
M30x3.5	26.5		M22x2	20
M33x3.5	29.5		M24x1.5	22.5
M36x4	32		M24x2	22
M39x4	35		M26x1.5	24.5
M42x4.5	37.5		M27x1.5	25.5
M45x4.5	40.5		M27x2	25
M48x5	43		M28x1.5	26.5
M52x5	47		M30x1.5	28.5
M56x5.5	50.5		M30x2	28
M60x5.5	54.5		M33x2	31
M64x6	58		M36x3	33
M68x6	60		M39x3	36