Whitworth Pipe thread

Ø Threads per Inch pilot holeØ mm Millimeter Inch
Decimal
1/8 28 8,80 9,73 0,3831
1/4 19 11,80 13,16 0,5181
3/8 19 15,25 16,66 0,6559
1/2 14 19,00 20,96 0,8252
5/8 14 21,00 22,91 0,9020
3/4 14 24,50 26,44 1,0409
7/8 14 28,25 30,20 1,1890
1 11 30,75 33,25 1,3091
1.1/8 11 35,50 37,90 1,4921
1.1/4 11 39,50 41,91 1,6500
1.3/8 11 42,00 44,32 1,7449
1.1/2 11 45,50 47,80 1,8819
1.3/4 11 51,40 53,75 2,1610
2 11 57,20 59,62 2,3472