August 27, 2014
3615 view(s)
BRASS THREADS (British Standard Brass)
BSB - Brass threads are used for brass tubing with a uniform wall thickness regardless of the tube diameter. 26 Threads per inch is the standard on all tube diameters.
The reason for using 26 tpi, is brass tube has a almost the same wall thickness irrespective of the outside diameter of the tube, therefore as BSW thread depths are determined by the threads per inch, a lower tpi would reduce the strength of the tube or cut right through it.
The included thread angle on all BSB threads is 55 degrees
Nominal sizes range from 1⁄8 to 2 inches. Thread Check supplies a complete range of thread gages.
| Thread Form Data | Tapping Hole | |||||||
| Diameter | O/D | Core | Pitch | Depth | Radius | Effective Dia | T.P.I | Dec / Met / Frac |
| 1/8" | 0.125 | 0.0757 | 0.03846 | 0.0246 | -- | 0.1020 | 26 | Number 47 |
| 1/4" | 0.250 | 0.2007 | 0.03846 | 0.0246 | -- | 0.2254 | 26 | Number 6 |
| 3/8" | 0.375 | 0.3257 | 0.03846 | 0.0246 | -- | 0.3504 | 26 | Letter Q |
| 1/2" | 0.500 | 0.4507 | 0.03846 | 0.0246 | -- | 0.4754 | 26 | 29/64" |
| 5/8" | 0.625 | 0.5657 | 0.03846 | 0.0246 | -- | 0.6004 | 26 | 37/64" |
| 3/4" | 0.750 | 0.7007 | 0.03846 | 0.0246 | -- | 0.7254 | 26 | 45/64" |
| 7/8" | 0.875 | 0.8257 | 0.03846 | 0.0246 | -- | 0.8504 | 26 | 53/64" |
| 1" | 1.000 | 0.9507 | 0.03846 | 0.0246 | -- | 0.9754 | 26 | 61/64" |
| 1-1/8" | 1.125 | 1.0757 | 0.03846 | 0.0246 | -- | 1.1004 | 26 | 1-5/64" |
| 1-1/4" | 1.250 | 1.2007 | 0.03846 | 0.0246 | -- | 1.2254 | 26 | 1-13/64" |
| 1-1/2" | 1.500 | 1.4507 | 0.03846 | 0.0246 | -- | 1.4754 | 26 | 1-29/64" |
