BA British Association

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Material Special Tool Steel
Hardness 58° to 60° HRC

HT-104

BA (British Association)

Thread Angle 55°

Size No. Major Diameter of Threads in Inches Threads Per Inch No. of FLutes A
Overall Length Inches
B
Thread Length Inches
C
Shank Diameter Inches
0 0.2362 25.4 3 2-1/2 1 0.242
1 0.2087 28.2 3 2-3/8 7/8 0.213
2 0.1850 31.4 3 2-3/8 7/8 0.189
3 0.1614 34.8 3 2-1/8 3/4 0.166
4 0.1417 38.5 3 2 11/16 0.144
5 0.1260 43.0 3 1-15/16 5/8 0.128
6 0.1102 47.9 3 1-7/8 9/16 0.128
7 0.0984 52.9 3 1-13/16 1/2 0.128
8 0.0866 59.1 3 1-3/4 7/16 0.128
9 0.0748 65.1 3 1-11/16 3/8 0.128
10 0.0669 72.6 3 1-5/8 5/16 0.128

Notes:

BA hand taps are supplied in a set of three pieces (Taper, Second & Bottoming).
You can order any Taper also.

Bottoming 1 1/2 threads chmfered use after threads have been started for tapping to bottom of holes, 23" per side

Second 3 to 5 threads chamfered for general use when tapping to bottom of holes is not optical 8" per side

Taper 8 to 10 threads chamfered for easy thread starting in rough material, 4" per side