"Jim Carriere" wrote in message
...
Bill Chernoff wrote:


I'm not sure where a regular person finds a #18 bit. Aircraft Spruce
doesn't list them. Ace Hardware lists them for about three bucks, I don't
know if the stores normally stock them. Home Depot Aerospace does not. I
might use the next smallest size, and after cleaning up the burrs with a
countersink it will probably turn out close enough.

Places like Harbor Freight sell drill sets that cover the common fractional,
number and letter sizes for around $40. At that price everybody can have
just about every drill size they'll ever need.



For screw sizes, umm, well, the 3 1/8 turn needle kit I got from Aircraft
Spruce came with brass 6-32 screws. Specifically, MS35214-29, which are
6-32 x 3/4. I just checked the fit, and I don't think they'll be quite
long enough, so I'll probably order several -31 (1" long) when I order
hardware for all my other instruments.

6-32 has been the standard size for instrument screws, brass screws limit
the amount of magnetic material in the vicinity of the compass.
Instruments that aren't threaded or have a captive nut usually have a hole
somewhat larger than the body of a #6 screw, this is to allow for the "legs"
of the commonly used NAS 487 instrument nut.