THREADING SYSTEMS - JEL - 05/2008 - Komet

Tap drill diameters for milled and cut threads
G
Pipe Thread DIN EN ISO 228
RP
ISO 7/1, DIN 2999-1,
DIN EN 10226-1
Size Nom. Ø Pitch t.p.i. Tap drill Ø Size Nom. Ø Pitch t.p.i. Tap drill Ø
G 1/8“ 9,728 28 8,90 RP 1/16 7,723 28 6,55
G 1/4“ 13,157 19 11,70 RP 1/8 9,728 28 8,60
G 3/8“ 16,662 19 15,40 RP 1/4 13,157 19 11,50
G 1/2“ 20,955 14 19,10 RP 3/8 16,662 19 15,00
G 5/8“ 22,911 14 21,10 RP 1/2 20,955 14 18,50
G 3/4“ 26,441 14 24,60 RP 3/4 26,441 14 24,00
G 7/8“ 30,201 14 28,40 RP 1“ 33,249 11 30,25
G 1“ 33,249 11 30,80 RP 1 1/4“ 41,910 11 39,00
G 1 1/8“ 37,897 11 35,50 RP 1 1/2“ 47,803 11 44,85
G 1 1/4“ 41,910 11 39,50 RP 2“ 59,614 11 56,50
G 1 3/8“ 44,323 11 41,90
G 1 1/2“ 47,803 11 45,40
G 1 3/4“ 53,746 11 51,40
G 2“ 59,614 11 57,20
G 2 1/4“ 65,710 11 63,20
G 2 1/2“ 75,184 11 72,80
G 2 3/4“ 81,834 11 79,10
G 3“ 87,884 11 85,50
BSF
Whitworth Fine Thread
NPSF
American Cylindrical
Pipe Thread
Size Nom. Ø Pitch t.p.i. Tap drill Ø Size Nom. Ø Pitch t.p.i. Tap drill Ø
1/4“ 6,350 26 5,30 NPSF 1/16 7,582 27 6,35
9/32“ 7,142 26 6,10 NPSF 1/8 9,929 27 8,75
5/16“ 7,938 22 6,80 NPSF 1/4 13,236 18 11,30
3/8“ 9,525 20 8,30 NPSF 3/8 16,673 18 14,75
7/16“ 11,113 18 9,70 NPSF 1/2 20,819 14 18,20
1/2“ 12,700 16 11,10 NPSF 3/4 26,166 14 23,50
9/16“ 14,288 16 12,70 NPSF 1“ 32,718 11/2 29,50
5/8“ 15,875 14 14,00
11/16“ 17,463 14 15,50
3/4“ 19,050 12 16,75
13/16“ 20,638 12 18,50
7/8“ 22,225 11 19,75
1“ 25,400 10 22,75
1 1/8“ 28,575 9 25,50
1 1/4“ 31,750 9 28,75
1 3/8“ 34,925 8 31,50
1 1/2“ 38,100 8 34,80
1 5/8“ 41,275 8 38,00
1 3/4“ 44,450 7 40,50
2“ 50,800 7 47,00
10
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