"W. Curtiss Priest" hath wroth:

also ... important ... the sewing needle is much
larger than this hole ... we are just using the
sharp point on the tip of the needle. And, the
size of the point does not always correspond to
the size of the needle, but, in general, the finer
needles have sharper points in the last 1 or 2 mils
of their length

Then I was making pinhole cameras in skool, I had nothing but trouble
using sewing needles to make the pinhole in aluminium or brass foil. I
read an old book that suggested using tiny cactus needles. I tried it
and found that it makes a much smaller and cleaner hole (when viewed
with a microscope). The needles have almost no bending strength but
are very strong inline with the point (as long as the needle isn't
bent). Building a tool to hold the cactus needle was tricky, but I
was impatient and just used tweezers.

Way off topic but interesting... pinhole eyeglasses:
http://www.pinholes.com

Pinhole FAQ:
http://glsmyth.com/Pinhole/Articles/FAQ/pin_faq.htm

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558