I got this information from this PDF by
Stephen G. Wellcome, which has lots more information on drill and
tap sizes for several standards, including:
- British Association (BA)
- British Standard Fine (BSF)
- British Standard Whitworth (BSW)
- ISO Metric (MM)
- National Coarse (NC)
- National Fine (NF)
Below is only a small segment of the PDF, just the diameter
of numbered and lettered drill bits.
| Drill | Size
|
|---|
| 80 | .0135"
|
| 79 | .0145"
|
| 78 | .0160"
|
| 77 | .0180"
|
| 76 | .0200"
|
| 75 | .0210"
|
| 74 | .0225"
|
| 73 | .0240"
|
| 72 | .0250"
|
| 71 | .0260"
|
| 70 | .0280"
|
| 69 | .0292"
|
| 68 | .0310"
|
| 67 | .0320"
|
| 66 | .0330"
|
| 65 | .0350"
|
| 64 | .0360"
|
| 63 | .0370"
|
| 62 | .0380"
|
| 61 | .0390"
|
| 60 | .0400"
|
| 59 | .0410"
|
| 58 | .0420"
|
| 57 | .0430"
|
| 56 | .0465"
|
| 55 | .0520"
|
| 54 | .0550"
|
| Drill | Size
|
|---|
| 53 | .0595"
|
| 52 | .0635"
|
| 51 | .0670"
|
| 50 | .0700"
|
| 49 | .0730"
|
| 48 | .0760"
|
| 47 | .0785"
|
| 46 | .0810"
|
| 45 | .0820"
|
| 44 | .0860"
|
| 43 | .0890"
|
| 42 | .0935"
|
| 41 | .0960"
|
| 40 | .0980"
|
| 39 | .0995"
|
| 38 | .1015"
|
| 37 | .1040"
|
| 36 | .1065"
|
| 35 | .1100"
|
| 34 | .1110"
|
| 33 | .1130"
|
| 32 | .1160"
|
| 31 | .1200"
|
| 30 | .1285"
|
| 29 | .1360"
|
| 28 | .1405"
|
| 27 | .1440"
|
| Drill | Size
|
|---|
| 26 | .1470"
|
| 25 | .1495"
|
| 24 | .1520"
|
| 23 | .1540"
|
| 22 | .1570"
|
| 21 | .1590"
|
| 20 | .1610"
|
| 19 | .1660"
|
| 18 | .1695"
|
| 17 | .1730"
|
| 16 | .1770"
|
| 15 | .1800"
|
| 14 | .1820"
|
| 13 | .1850"
|
| 12 | .1890"
|
| 11 | .1910"
|
| 10 | .1935"
|
| 9 | .1960"
|
| 8 | .1990"
|
| 7 | .2010"
|
| 6 | .2040"
|
| 5 | .2055"
|
| 4 | .2090"
|
| 3 | .2130"
|
| 2 | .2210"
|
| 1 | .2280"
|
| Drill | Size
|
|---|
| A | .2340"
|
| B | .2380"
|
| C | .2420"
|
| D | .2460"
|
| E | .2500"
|
| F | .2570"
|
| G | .2610"
|
| H | .2660"
|
| I | .2720"
|
| J | .2770"
|
| K | .2810"
|
| L | .2900"
|
| M | .2950"
|
| N | .3020"
|
| O | .3160"
|
| P | .3230 "
|
| Q | .3320"
|
| R | .3390"
|
| S | .3480"
|
| T | .3580"
|
| U | .3680"
|
| V | .3770"
|
| W | .3860"
|
| X | .3970"
|
| Y | .4040"
|
| Z | .4130"
|