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
BA
47.5° thread form
Size inch
Threads per inch
Tapping Drill Sizes
Preferred mm - inch
Alternative mm - inch
0
1.00
5.1
13/64
5.0
1
0.90
4.5
4.4
11/64
2
0.81
4.0
5/32
3.9
3
0.73
3.4
3.3
4
0.66
3.0
2.95
5
0.59
2.7
2.6
6
0.53
2.35
2.25
7
0.48
2.1
2.0
5/64
8
0.43
1.8
1.75
9
0.39
1.55
1.5
10
0.35
1.4
1.35
11
0.31
1.2
3/64
1.15
12
0.28
1.05
1.0
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.
