Specifications of International Thread Standards

British Standard Whitworth Coarse Thread Series (parallel, cylindrical)
In GB most common Thread. Corresponds to the Metric Thread in its type of use.
The flank angle is 55°.

Nominal
Diameter
Major
Diameter
Inch
Major
Diameter
mm
Tapping
Drill Size
mm
TPIPitch
mm
W 1/16"1/161.5881.05600.423
W 3/32"3/322.3811.70480.529
W 1/8"1/83.1752.36400.635
W 5/32"5/323.9692.95320.794
W 3/16"3/164.7633.41241.058
W 7/32"7/325.5564.20241.058
W 1/4"1/46.3504.72201.270
W 5/16"5/167.9406.13181.411
W 3/8"3/89.5257.49161.587
W 7/16"7/1611.1138.79141.814
W 1/2"1/212.7009.99122.117
W 9/16"9/1614.28811.58122.117
W 5/8"5/815.87512.92112.309
W 3/4"3/419.05015.80102.540
W 7/8"7/822.22518.6192.822
W 1"125.40021.3483.175
W 1 1/8"1 1/828.57523.9373.628
W 1 1/4"1 1/431.75027.1173.628
W 1 3/8"1 3/834.92529.5164.233
W 1 1/2"1 1/238.10032.6864.233
W 1 5/8"1 5/841.27534.7755.080
W 1 3/4"1 3/444.45037.9555.080
W 1 7/8"1 7/847.62540.404.55.644
W 2"250.80043.584.55.644
W 2 1/4"2 1/257.15049.0246.350
W 2 1/2"2 1/263.50055.3746.350
W 2 3/4"2 3/469.85060.563.57.257
W 3"376.20066.913.57.257
W 3 1/4"3 1/482.55072.553.257.815
W 3 1/2"3 1/288.90078.903.257.815
W 3 3/4"3 3/495.25084.4138.467
W 4"4101.60090.7638.467
Whitworth Coarse Thread