9. Comparison of pitch diameter tolerance
For Forming Tap Unified Fine Thread (UNF) Intro
Basic Pitch (+) μm
Dia.
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420

3B 3BX 2BX 42 SP
No.0-80 UNF 2B G3 G5 57
H2

3B 3BX 2BX 47
SL
No1-72 UNF 2B G3 G5 63
3BX, Class G, Class H for 3B internal threads
H2
2BX, Class G, Class H for 2B internal threads
3B 3BX 2BX 50 internal threads 3B
No.2-64 UNF 2B G4 68 PO
internal threads 2B
H2 H3

3B 3BX 2BX 53
No.3-56 UNF 2B G4 71
ST
H2 H3

3B 3BX 2BX 58
No.4-48 UNF 2B G4 G5 78
H3 H5
ROLL
3B 3BX 2BX 60
No.5-44 UNF 2B G4 G5 80
H3 H5 CARBIDE
3B 3BX 2BX 63
No.6-40 UNF 2B G5 86
H3 H5
LONG
3B 3BX 2BX 67
No.8-36 UNF 2B G5 90
H3 H5
HAND
3B 3BX 2BX 73
TAPS
No.10-32 UNF 2B G5 G6 G7 98
H4 H6
EG (STI)
3B 3BX 2BX 77
No.12-28 UNF 2B G6 105
H4 H6
SPECIAL
3B 3BX 2BX 81 THREADS,
1/4-28 UNF 2B G6 G7 108 GAUGES
H4 H6

3B 3BX 2BX 90 THREAD
5/16-24 UNF 2B G6 121 MILLS
H5 H7

3B 3BX 2BX 93
3/8-24 UNF 2B G7 124
DIES
H5 H7

3B 3BX 2BX 104
7/16-20 UNF 2B G7 137
CENTER
H5 H7
DRILLS
3B 3BX 2BX 106
1/2-20 UNF 2B G7 141 Technical
H5 H7 info

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