As for screws. =20
2-56, 4-40, 6-32, ... are screws.
The second part stands for threads per inch.  So a 4-40 has 40 threads =
per inch.  I don't know what the 1st number means
=20
THREAD/SCREW - Drill, Tap, & Clearance Hole Chart Information




      Machine Screw
      Size Threads
      Per Inch Minor
      Dia Tap Drills Clearance Hole Drills=20
      Alum, Brass,
      & Plasitcs=20
      75% Thread
     Stainless Steel,
      Steels & Iron=20
      50% Thread
     All Materials=20
      Close Fit Free Fit=20
      # or Dia Major
      Dia Drill
      Size Decimal
      Equiv. Drill
      Size Decimal
      Equiv. Drill
      Size Decimal
      Equiv. Drill
      Size Decimal
      Equiv.=20
      0 .0600 80 .0447 3/64 .0469 55 .0520 52 .0635 50 .0700=20
      1 .0730 64 .0538 53 .0595 1/16 .0625 48 .0760 46 .0810=20
      72 .0560 53 .0595 52 .0635=20
      2 .0860 56 .0641 50 .0700 49 .0730 43 .0890 41 .0960=20
      64 .0668 50 .0700 48 .0760=20
      3 .0990 48 .0734 47 .0785 44 .0860 37 .1040 35 .1100=20
      56 .0771 45 .0820 43 .0890=20
      4 .1120 40 .0813 43 .0890 41 .0960 32 .1160 30 .1285=20
      48 .0864 42 .0935 40 .0980=20
      5 .125 40 .0943 38 .1015 7/64 .1094 30 .1285 29 .1360=20
      44 .0971 37 .1040 35 .1100=20
      6 .138 32 .0997 36 .1065 32 .1160 27 .1440 25 .1495=20
      40 .1073 33 .1130 31 .1200=20
      8 .1640 32 .1257 29 .1360 27 .1440 18 .1695 16 .1770=20
      36 .1299 29 .1360 26 .1470=20
      10 .1900 24 .1389 25 .1495 20 .1610 9 .1960 7 .2010=20
      32 .1517 21 .1590 18 .1695=20
      12 .2160 24 .1649 16 .1770 12 .1890 2 .2210 1 .2280=20
      28 .1722 14 .1820 10 .1935=20
      32 .1777 13 .1850 9 .1960=20
      1/4 .2500 20 .1887 7 .2010 7/32 .2188 F .2570 H .2660=20
      28 .2062 3 .2130 1 .2280=20
      32 .2117 7/32 .2188 1 .2280=20
      5/16 .3125 18 .2443 F .2570 J .2770 P .3230 Q .3320=20
      24 .2614 I .2720 9/32 .2812=20
      32 .2742 9/32 .2812 L .2900=20
      3/8 .3750 16 .2983 5/16 .3125 Q .3320 W .3860 X .3970=20
      24 .3239 Q .3320 S .3480=20
      32 .3367 11/32 .3438 T .3580=20
      7/16 .4375 14 .3499 U .3680 25/64 .3906 29/64 .4531 15/32 .4687=20
      20 .3762 25/64 .3906 13/32 .4062=20
      28 .3937 Y .4040 Z .4130=20
      1/2 .5000 13 .4056 27/64 .4219 29/64 .4531 33/64 .5156 17/32 .5312 =

      20 .4387 29/64 .4531 15/32 .4688=20
      28 .4562 15/32 .4688 15/32 .4688=20
      9/16 .5625 12 .4603 31/64 .4844 33/64 .5156 37/64 .5781 19/32 =
.5938=20
      18 .4943 33/64 .5156 17/32 .5312=20
      24 .5114 33/64 .5156 17/32 .5312=20
      5/8 .6250 11 .5135 17/32 .5312 9/16 .5625 41/64 .6406 21/32 .6562=20
      18 .5568 37/64 .5781 19/32 .5938=20
      24 .5739 37/64 .5781 19/32 .5938=20
      11/16 .6875 24 .6364 41/64 .6406 21/32 .6562 45/64 .7031 23/32 =
.6562=20
      3/4 .7500 10 .6273 21/32 .6562 11/16 .6875 49/64 .7656 25/32 .7812 =

      16 .6733 11/16 .6875 45/64 .7031=20
      20 .6887 45/64 .7031 23/32 .7188=20
      13/16 .8125 20 .7512 49/64 .7656 25/32 .7812 53/64 .8281 27/32 =
.8438=20
      7/8 .8750 9 .7387 49/64 .7656 51/64 .7969 57/64 .8906 29/32 .9062=20
      14 .7874 13/16 .8125 53/64 .8281=20
      20 .8137 53/64 .8281 27/32 .8438=20
      15/16 .9375 20 .8762 57/64 .8906 29/32 .9062 61/64 .9531 31/32 =
.9688=20
      1 1.000 8 .8466 7/8 .8750 59/64 .9219 1-1/64 1.0156 1-1/32 1.0313=20
      12 .8978 15/16 .9375 61/64 .9531=20
      20 .9387 61/64 .9531 31/32 .9688=20
      1-1/16 1.0625 18 .9943 1.000 1.000 1-1/64 1.0156 1-5/64 1.0781 =
1-3/32 1.0938=20
      1-1/8 1.1250 7 .9497 63/64 .9844 1-1/32 1.0313 1-9/64 1.1406 =
1-5/32 1.1562=20
      12 1.0228 1-3/64 1.0469 1-5/64 1.0781=20
      18 1.0568 1-1/16 1.0625 1-5/64 1.0781=20
      1-3/16 1.1875 18 1.1193 1-1/8 1.1250 1-9/64 1.1406 1-13/64 1.2031 =
1-7/32 1.2188=20
      1-1/4
     1.2500
     7 1.0747 1-7/64 1.1094 1-5/32 1.1562 1-17/64
     1.2656
     1-9/32
     1.2812
    =20
      12 1.1478 1-11/64 1.1719 1-13/64 1.2031=20
      18 1.1818 1-3/16 1.1875 1-13/64 1.2031=20
      1-5/16 1.3125 18 1.2443 1-1/4 1.2500 1-17/64 1.2656 1-21/64 1.3281 =
1-11/32 1.3438=20
      1-3/8 1.3750 6 1.1705 1-7/32 1.2187 1-17/64 1.2656 1-25/64 1.3906 =
1-13/32 1.4062=20
      12 1.2728 1-19/64 1.2969 1-21/64 1.3281=20
      18 1.3068 1-5/16 1.3125 1-21/64 1.3281=20
      1-7/16 1.4375 18 1.3693 1-3/8 1.3750 1-25/64 1.3906 1-29/64 1.4531 =
1-15/32 1.4688=20
      1-1/2 1.500 6 1.2955 1-11/32 1.3437 1-25/64 1.3906 1-33/64 1.5156 =
1-17/32 1.5312=20
      12 1.3978 1-27/64 1.4219 1-7/16 1.4375=20
      18 1.4318 1-7/16 1.4375 1-29/64 1.4531=20
      1-9/16 1.5625 18 1.4943 1-12 1.500 1-33/64 1.5156 1-37/64 1.5781 =
1-19/32 1.5938=20
      1-5/8 1.625 18 1.5568 1-9/16 1.5625 1-37/64 1.5781 1-41/64 1.6406 =
1-21/32 1.6562=20
      1-11/16 1.6875 18 1.6193 1-5/8 1.6250 1-41/64 1.6406 1-45/64 =
1.7031 1-23/32 1.7188=20
      1-3/4 1.750 5 1.5046 1-9/16 1.5625 1-5/8 1.6250 1-49/64 1.7659 =
1-25/32 1.7812=20


I can help with drill sizes.
The decimal is in inches




      NUMBER DRILL SIZES=20
           =20
      No. Decimal equiv. No. Decimal equiv. No. Decimal equiv. No. =
Decimal equiv.=20
      1 0.2280 21 0.1590 41 0.0960 61 0.0390=20
      2 0.2210 22 0.1570 42 0.0935 62 0.0380=20
      3 0.2130 23 0.1540 43 0.0890 63 0.0370=20
      4 0.2090 24 0.1520 44 0.0860 64 0.0360=20
      5 0.2055 25 0.1495 45 0.0820 65 0.0350=20
      6 0.2040 26 0.1470 46 0.0810 66 0.0330=20
      7 0.2010 27 0.1440 47 0.0785 67 0.0320=20
      8 0.1990 28 0.1405 48 0.0760 68 0.0310=20
      9 0.1960 29 0.1360 49 0.0730 69 0.02925=20
      10 0.1935 30 0.1285 50 0.0700 70 0.0280=20
      11 0.1910 31 0.1200 51 0.0670 71 0.0260=20
      12 0.1890 32 0.1160 52 0.0635 72 0.0250=20
      13 0.1850 33 0.1130 53 0.0595 73 0.0240=20
      14 0.1820 34 0.1110 54 0.0550 74 0.0225=20
      15 0.1800 35 0.1100 55 0.0520 75 0.0210=20
      16 0.1770 36 0.1065 56 0.0465 76 0.0200=20
      17 0.1730 37 0.1040 57 0.0430 77 0.0180=20
      18 0.1695 38 0.1015 58 0.0420 78 0.0160=20
      19 0.1660 39 0.0995 59 0.0410 79 0.0145=20
      20 0.1610 40 0.0980 60 0.0400 80 0.0135=20
           =20
           =20
           =20
           =20


      LETTER DRILL SIZES     =20
           =20
      A 0.234 N 0.302    =20
      B 0.238 O 0.316    =20
      C 0.242 P 0.323    =20
      D 0.246 Q 0.331    =20
      E 0.250 R 0.339    =20
      F 0.257 S 0.348    =20
      G 0.261 T 0.358    =20
      H 0.266 U 0.368    =20
      I 0.272 V 0.377    =20
      J 0.277 W 0.386    =20
      K 0.281 X 0.397    =20
      L 0.290 Y 0.404    =20
      M 0.295 Z 0.413    =20


----- Original Message -----=20
From: "Tal Bejerano - AMC" <kooter@ZAHAV.NET.IL>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, February 18, 2002 2:11 PM
Subject: [PICLIST] [EE]: American standards??


> Hi 2 All
>=20
> I found many circuits that talking about "#16 wire" or "#8 Screws" "22 =
gauge
> wire". what are this measurements?
> where can I find converter for this measurements?
>=20
> Thanks
>=20
> Tal
>=20
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>=20
>=20
>=20

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.