TAP DRILL SIZES BASED ON
APPROXIMATELY 75% FULL THREAD

NATIONAL COURSE AND
FINE THREADS

THREAD

#0-80
#1-64
#1-72
#2-56
#2-64
#3-48
#3-56
#4-40
#4-48
#5-40
#5-44
#6-32
#6-40
#8-32
#8-36
3/16-24
#10-24
#10-32
#12-24
#12-28
1/4-20
1/4-28
5/16-18
5/16-24
3/8-16
3/8-24
7/16-14
7/16-20
1/2-12
1/2-13
1/2-20
9/16-12
9/16-18
5/8-11
5/8-18
3/4-10
3/4-16
7/8-9
7/8-14
1-8
1-12
1-14
1 1/8-7
1 1/8-12
1 1/4-7
1 1/4-12
1 1/2-6
1 1/2-12
1 3/4-5
2-4 1/2
2-12
2 1/4-4 1/2

DRILL

3/64
NO. 53
NO. 53
NO. 51
NO. 50
5/64
NO. 46
NO. 43
NO. 42
NO. 39
NO. 37
NO. 36
NO. 33
NO. 29
NO. 29
NO. 26
NO. 25
NO. 21
NO. 17
NO. 15
NO. 7
NO. 3
F
I
5/16
Q
U
W
27/64
27/64
29/64
31/64
33/64
17/32
37/64
21/32
11/16
49/64
13/16
7/8
59/64
15/16
63/64
1 3/64
1 7/64
1 11/64
1 11/32
1 27/64
1 9/16
1 43/64
1 59/64
2 1/32

TAPER PIPE
(NPT)

STRAIGHT PIPE
(NPTF DRY SEAL)

THREAD

1/8-27
1/4-18
3/8-18
1/2-14
3/4-14
1-11 1/2
1 1/4-11 1/2
1 1/2-11 1/2
2-11 1/2
2 1/2-8
3-8

DRILL

R
7/16
37/64
23/32
59/64
1 5/32
1 1/2
1 47/64
2 7/32
2 41/64
3 17/64

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