BSW

BRITISH STANDARD WHITWORTH

55 Degree Threads

SIZE TPI EXTERNAL INTERNAL DRILL SIZE DRILL SIZE
BSW 55   MAJORS MINORS CLEARANCE HOLE TAPPED HOLE
    INCH MM INCH MM INCH MM INCH MM
1/16 60 0.0620 1.59 0.0410 1.05   1.99  
1.15
3/32 48 0.0940 2.38 0.0670 1.70   2.67  
1.90
1/8 40 0.1250 3.18 0.0930 2.36 9/64 3.57 # 38
2.60
5/32 32 0.1560 3.97 0.1160 2.95 11/64 4.37 1/8
3.20
3/16 24 0.1870 4.75 0.1340 3.40 13/64 5.16 # 27
3.70
7/32 24 0.2190 5.60 0.1660 4.22 15/64 5.95 # 19
4.30
1/4 20 0.2500 6.35 0.1860 4.72 17/64 6.75 # 9
5.00
5/16 18 0.3120 7.92 0.2410 6.12 21/64 8.33 1/4
6.40
3/8 16 0.3750 9.53 0.2950 7.49 25/64 9.92 5/16
8.00
7/16 14 0.4370 11.10 0.3460 8.79 29/64 11.51 U
9.40
1/2 12 0.5000 12.70 0.3930 9.98 17/32 13.49 27/64
10.80
9/16 12 0.5630 14.29 0.4560 11.58 19/32 15.08 15/32
12.00
5/8 11 0.6250 15.88 0.5090 12.93 21/32 16.67 17/32
13.50
11/16 11 0.6880 17.48 0.5710 14.50   17.75  
15.00
3/4 10 0.7500 19.05 0.6220 15.80 25/32 19.84 21/32
17.00
13/16 10 0.8130 20.65 0.6840 17.37   21.00  
18.00
7/8 9 0.8750 22.23 0.7330 18.62 29/32 23.02 49/64
19.50
15/16 9 0.9380 23.83 0.7950 20.19   24.00  
20.75
1 8 1.0000 25.40 0.8400 21.34 1 1/16 26.99 7/8
22.50
1 1/8 7 1.1250 28.58 0.9420 23.93 1 3/16 30.16 1
25.50
1 1/4 7 1.2500 31.75 1.0670 27.10 1 5/16 33.34 1 7/16
28.50
1 3/8 6 1.3750 34.93 1.1620 29.51 1 7/16 36.51 1 7/32
31.00
1 1/2 6 1.5000 38.10 1.2870 32.69 1 9/16 39.69 1 11/32
34.50
1 5/8 5 1.6250 41.28 1.3690 34.77   41.50  
35.50
1 3/4 5 1.7500 44.45 1.4940 37.95   45.00  
38.50
1 7/8 4.5 1.8750 47.63 1.5910 40.40   48.00  
41.25
2 4.5 2.0000 50.80 1.7150 43.57   51.00  
44.50
2 1/4 4              
50.00