BSF

BRITISH STANDARD FINE 

      55 Degree Threads      

SIZE

TPI

EXTERNAL

INTERNAL

DRILL SIZE

DRILL SIZE

BSF 55

 

MAJORS

MINORS

CLEARANCE HOLE

TAPPED HOLE

    INCH MM INCH MM INCH MM INCH MM
3/16 32 0.1875 4.76 0.1475 3.75   4.90 # 22 4.00
7/32 28 0.2188 5.56 0.1730 4.39   5.70 # 15 4.60
1/4 26 0.2500 6.35 0.2000 5.08 17/64 6.75 # 3 5.50
9/32 26 0.2800 7.14 0.2300 5.89       6.10
5/16 22 0.3125 7.94 0.2540 6.45 21/64 8.33 17/64 6.75
3/8 20 0.3750 9.53 0.3110 7.90 25/64 9.92 21/64 8.33
7/16 18 0.4375 11.11 0.3660 9.30 29/64 11.51 3/8 9.53
1/2 16 0.5000 12.70 0.4200 10.67 17/32 13.49 7/16 11.11
9/16 16 0.5625 14.29 0.4820 12.24 19/32 15.08 1/2 12.70
5/8 14 0.6250 15.88 0.5330 13.54 21/32 16.67 9/16 14.29
11/16 14 0.6875 17.46 0.5960 15.14   17.75   15.50
3/4 12 0.7500 19.05 0.6430 16.33 25/32 19.84 43/64 17.07
13/16 12 0.8100 20.64 0.7100 17.92       18.25
7/8 11 0.8750 22.23 0.7590 19.28 29/32 23.02 25/32 19.84
1 10 1.0000 25.40 0.8750 22.15 1 1/16 26.99 29/32 23.02
1 1/8 9 1.1250 28.58 0.9830 24.97 1 3/16 30.16 1 1/64 25.80
1 1/4 9 1.2500 31.75 1.1080 28.14 1 5/16 33.34 1 9/64 28.97
1 3/8 8 1.3750 34.93 1.2150 30.86 1 7/16 36.51 1 1/4 31.75
1 1/2 8 1.5000 38.10 1.3400 34.04 1 9/16 39.69 1 3/8 34.93
1 5/8 8 1.6300 41.30 1.4600 37.21       37.50
1 3/4 7 1.7500 44.45 1.5670 39.80   45.00   41.00
2 7 2.0000 50.80 1.8170 46.15   52.00   47.00
2 1/4 6 2.2500 57.15 2.0366 51.73   58.00   53.00
2 1/2 6 2.5000 63.50 2.2866 58.08   64.00   58.00