Pipe Tap Drill Sizes
	Pipe Tap		Tap Drill Size				Pipe Tap		Tap Drill Size
	Nominal Pipe Tap		Taper NPT		Straight NPS		Nominal Pipe Tap		Taper NPT		Straight NPS
	1/16-27		#D		1/4"		3/4-14		59/64"		15/16"
	1/8-27		#R		#S		1.0-11.5		1-5/32"		1-3/16"
	1/4-28		7/16"		29/64"		1.25-11.5		1-1/2"		1-33/64"
	3/8-18		37/64"		19/32"		1.50-11.5		1-47/64"		1-3/4"
	1/2-14		23/32"		47/64"		2.0-11.5		2-7/32"		2-7/32"

Metric Tap Drill Sizes
Tap Size		Tap Drill Size		Tap Size		Tap Drill Size		Tap Size		Tap Drill Size
M2 x .4		1.60mm		M10 x 1.5		8.5mm		M18 x 2.5		15.5mm
M2.5 x .45		2.05mm		M10 x 1.25		8.75mm		M18 x 1.5		16.5mm
M3 x .5		2.5mm		M12 x 1.75		10.25mm		M20 x 2.5		17.5mm
M4 x .7		3.3mm		M12 x 1.25		10.75mm		M20 x 1.5		18.5mm
M5 x .8		4.2mm		M14 x 2.0		12mm		M24 x 3.0		21mm
M6 x 1.0		5mm		M14 x 1.5		12.5mm		M30 x 3.5		26.5mm
M8 x 1.25		6.75mm		M16 x 2.0		14mm		M36 x 4.0		32mm
M8 x 1.0		7mm		M16 x 1.5		14.5mm

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Hole size for tapping screws
Nominal Screw Size		Type A, AB		Type F		Nominal Screw Size		Type A, AB		Type F		Nominal Screw Size		Type A, AB		Type F
#2		#48		#49		#3		#46		#46		#4		#44		#44
#5		#36		#37		#6		#32		#31		#7		#30
#8		#29		#26		#10		#21				#10	Course thread			#17
#10	Fine thread			#16		#12		3/16"		#8		#14	1/4"	5.5mm		#1

Smith Fastener Company, A California Corporation - 3613 East Florence Avenue, Bell, California, 90201 - Phone: ( 323 ) 587-0382 - FAX: ( 323 ) 587-8712 - E-mail: sales@smithfast.com - Copyright © 2000 by Smith Fastener Company - Last updated: May 22nd, 2006 - http://www.smithfast.com/pipetap.htm