INCH TAP DRILL SIZES
Recommended tap drill sizes (for approx. 75% thread)
|
INCH SIZES NATIONAL COARSE |
INCH SIZES NATIONAL FINE |
TAP DRILL SIZE SIZE |
TAP DRILL SIZE SIZE |
#1-64 #53 #2-56 #51 #3-48 5/64" #4-40 #43 #5-40 #39 #6-32 #36 #8-32 #29 #10-24 #25 #12-24 #17 1/4-20 #7 5/16-18 F 3/8-16 5/16 7/16-14 U 1/2-13 27/64 9/16-12 31/64 5/8-11 17/32 3/4-10 21/32 7/8-9 49/64 1"-8 7/8 1-1/8-7 63/64 1-1/4-7 1-7/64 1-1/2-6 1-11/32 1-3/4-5 1-35/64 2"-4-1/2 1-25/32 |
#0-80 3/64" #1-72 #53 #2-64 #50 #3-56 #46 #4-48 #42 #5-44 #37 #6-40 #33 #8-36 #29 #10-32 #21 #12-28 #15 1/4-28 #3 5/16-24 I 3/8-24 Q 7/16-20 W 1/2-20 29/64 9/16-18 33/64 5/8-18 37/64 3/4-16 11/16 7/8-14 13/16 1"-14 15/16 1-1/8-12 1-3/64 1-1/4-12 1-11/64 1-1/2-12 1-27/64 1-3/4-12 1-43/64 2"-12 1-59/64 |
|
TAPER PIPE SIZES NPT |
STRAIGHT PIPE SIZES NPS |
TAP DRILL SIZE SIZE |
TAP DRILL SIZE SIZE |
1/8-27 R 1/4-18 7/16 3/8-18 37/64 1/2-14 23/32 3/4-14 59/64 1"-11-1/2 1-5/32 1-1/4-11-1/2 1-1/2 1-1/2-11-1/2 1-47/64 2"-11-1/2 2-7/32 2-1/2-8 2-5/8 3"-8 3-1/4 3-1/2-8 3-3/4 4"-8 4-1/4 |
1/8-27 S 1/4-18 29/64 3/8-18 19/32 1/2-14 47/64 3/4-14 15/16 1"-11-1/2 1-3/16 1-1/4-11-1/2 1-33/64 1-1/2-11-1/2 1-3/4 2"-11-1/2 2-7/32 2-1/2-8 2-21/32 3"-8 3-9/32 3-1/2-8 3-25/32 4"-8 4-9/32 |
METRIC TAP DRILL SIZES
Recommended tap drill sizes (for approx. 75% thread)
| METRIC COARSE SIZES | METRIC FINE SIZES |
TAP DRILL SIZE SIZE |
TAP DRILL SIZE SIZE |
1mm x .25 .75mm 1.1 x .25 .85 1.2 x .25 .95 1.4 x .3 1.1 1.6 x .35 1.25 1.7 x .35 1.3 1.8 x .35 1.45 2 x .4 1.6 2.2 x .45 1.75 2.5 x .45 2.05 3 x .5 2.5 3.5 x .6 2.9 4 x .7 3.3 4.5 x .75 3.7 5 x .8 4.2 6 x 1 5 7 x 1 6 8 x 1.25 6.8 9 x 1.25 7.8 10 x 1.5 8.5 11 x 1.5 9.5 12 x 1.75 10.2 14 x 2 12 16 x 2 14 18 x 2.5 15.5 20 x 2.5 17.5 22 x 2.5 19.5 24 x 3 21 27 x 3 24 30 x 3.5 26.5 33 x 3.5 29.5 36 x 4 32 39 x 4 35 |
4 mm x .35 3.6mm 4 x .5 3.5 5 x .5 4.5 6 x .5 5.5 6 x .75 5.25 7 x .75 6.25 8 x .5 7 8 x .75 7.25 8 x 1 7.5 9 x 1 8 10 x .75 9.25 10 x 1 9 10 x 1.25 8.8 11 x 1 10 12 x .75 11.25 12 x 1 11 12 x 1.5 10.5 14 x 1 13 14 x 1.25 12.8 14 x 1.5 12.5 16 x 1 15 16 x 1.5 14.5 18 x 1 17 18 x 2 16 20 x 1 19 20 x 1.5 18.5 20 x 2 18 22 x 1 21 22 x 1.5 20.5 22 x 2 20 24 x 1.5 22.5 24 x 2 22 26 x 1.5 24.5 27 x 1.5 25.5 27 x 2 25 28 x 1.5 26.5 30 x 1.5 28.5 30 x 2 28 33 x 2 31 36 x 3 33 39 x 3 36 |
Notes: Tap
Drill Sizes (inch) for a 75% Thread
In general, you can find the tap-drill for any size 60 degree thread, subtract
one pitch length from the major diameter.
Formula: Major Dia. minus One Pitch Length equals tap-drill size
English Example for 3/8-16 thread: .375 - .0625 = .3125 tap-drill (5/16)
Metric Example for M6 X 1 thread: 6mm - 1mm = 5mm tap-drill