DRILL AND TAPPING CHART
> BSW Whitworth
UNC UNS*
UNF UNS*
Metric ISO Course
Metric ISO Fine
BSF
BA
Metric Conduit
BSPT (Taper Pipe)
NPT (Taper Pipe)
NPS (Parallel Pipe)
BSPF (Parallel Pipe)
Brass
Spark Plug
BS Conduit
BSW Whitworth
55° thread form
Size inch
Threads per inch
Tapping Drill Sizes
Preferred mm - inch
Alternative mm - inch
1/16*
60
1.2
3/64
1.05
3/32*
48
1.9
1.75
1/8
40
2.55
2.5
3/32
5/32*
32
3.2
2.95
3/16
24
3.7
3.6
9/64
7/32*
4.5
4.3
11/64
1/4
20
5.1
5.0
5/16
18
6.5
6.4
3/8
16
7.9
7.8
19/64
7/16
14
9.5
9.2
23/64
1/2
12
10.5
13/32
9/16
12.0
15/32
5/8
11
13.5
17/32
33/64
3/4
10
16.5
41/64
16.0
7/8
9
19.0
47/64
1
8
22.0
55/64
27/32
1-1/8
7
31/32
24.5
61/64
1-1/4
28.0
1-3/32
27.5
1-5/64
1-1/2
6
33.5
1-5/16
33.0
1-19/64
1-3/4
5
39.0
1-17/32
38.5
1-33/64
2
4 1/2
44.5
1-49/64
44.0
Please note : Tradezone Ltd accepts no liability for any loss or damage either direct or consequential aising out of or in relation to the use or application of the information or products referred to herein.
