Tap drill size table and chart for Whitworth pipe thread

Standard ISO Hardware
Fastening Joining Assembly

The following as a Tap drill size table and chart for Whitworth pipe thread per DIN ISO 228. All dimensional data given in mm (millimeters)

Related: External ISO Pipe Thread Design Chart

Whitworth Pipe Thread Section View

Whitworth Pipe Thread Section View DIN ISO 228

Nominal
Diameter
Major
Diameter
Minor Diameter
Nut
Tapping
Drill Size
Threads
per Inch
Pitch
G 1/8"
9,73
8,85
8,80
28
0,907
G 1/4"
13,16
11,89
11,80
19
1,337
G 3/8"
16,66
15,39
15,25
19
1,337
G 1/2"
20,95
19,17
19,00
14
1,814
G 5/8"
22,91
21,13
21,00
14
1,814
G 3/4"
26,44
24,66
24,50
14
1,814
G 7/8"
30,20
28,42
28,25
14
1,814
G 1"
33,25
30,93
30,75
11
2,309
G 1 1/8"
37,90
35,58
35,30
11
2,309
G 1 1/4"
41,91
39,59
39,25
11
2,309
G 1 3/8"
44,32
42,00
41,70
11
2,309
G 1 1/2"
47,80
45,48
45,25
11
2,309
G 1 3/4"
53,74
51,43
51,10
11
2,309
G 2"
59,61
57,29
57,00
11
2,309
G 2 1/4"
65,71
63,39
63,10
11
2,309
G 2 1/2"
75,18
72,86
72,60
11
2,309
G 2 3/4"
81,53
79,21
78,90
11
2,309
G 3"
87,88
85,56
85,30
11
2,309
G 3 1/4"
93,98
91,66
91,50
11
2,309
G 3 1/2"
100,33
98,01
97,70
11
2,309
G 3 3/4"
106,68
104,30
104,00
11
2,309
G 4"
113,03
110,71
110,40
11
2,309

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