BA
BSC
BSF
BSP
BSTP
BSW
CEI
UNC
UNF
ME
BSB

BRITISH STANDARD BRASS

BRASS THREADS (British Standard Brass)
Because brass tubing has a uniform wall thickness, irrespective of the tube diameter, any thread cut on, (or in) it, would
have to have the same depth, so 26 tpi is standard on all diameters. An example would be the thread cut on the brass
trumpet horns of the 30s cars, although many were die-cast rather than brass. If it were 1" O/D, the thread would be 1"
Brass, 26tpi.


BSB has a 26 TPI pitch through the whole range and is often confused with BS Cycle thread the difference being that brass thread has an angle of 55 degrees whereas Cycle is 60 degrees. Brass threads are usually confined to fittings and adjusters on cables.
Brass thread taps and dies are sold and advertised as 26 tpi and are identified by the letters BSB.

These are a special order item.

Brass Pipe Screw Threads (Whitworth Form 55 Deg Thread Angle)
Dimensions in Inches except where stated

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"