Specifications of historical Thread Standards

Cycle Engineer Institution Thread, used in the British bicycle industry. Smetimes the name "BSC" or "BSCy" is used. This series replaced the Cycle Engineers Institute (CEI) thread. Though the two series are somewhat different.
The flank angle is 60°.

Major
Diameter
Inch
Major
Diameter
mm
Tapping
Drill Size
mm
TPIPitch
mm
0.0561.4220.965620.409
0.0641.6261.190620.409
0.0721.8291.393620.409
0.0802.0321.596620.409
0.0922.3371.854560.453
0.1042.6422.642440.577
0.1253.1752.499400.635
0.1543.9123.236400.635
0.1754.4453.600320.794
0.1874.7623.917320.794
0.2506.3505.309260.977
0.2666.7565.715260.977
0.2817.1376.096260.977
0.3127.9376.896260.977
0.3759.5258.484260.977
0.56214.28712.287201.270
1.00025.40024.359260.977
1.29032.76631.639241.058
1.37034.79733.670241.058
1.43736.51235.385241.058
1.50038.10036.973241.058
CEI Thread