On Apr 8, 4:32 pm, Jeff Liebermann
wrote:
"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.

Dear Mr. Liebermann,

I see that some folk simply have no patience to learn the fine art of
engineering and redesign. Really too bad. They might get a life.

As for using a cactus needle, this is truly interesting. I wonder if
such
needles are as small as 2 mil, or how their point is shaped? With
small
vise grips, gripping such things has become very predictable. One
would
feather the tightness on the cactus needle to the point it would not
slide, but
not so hard to crush it, to breaking.

Truly, the hole created with a sewing needle looks like a bullet
passed
through -- the copper is flared, thus the reason I put that "noise"
facing
away from the butane source. A cactus needle, of course, is barbed,
and
I presume it acts like a miniature rasp!

I'll try it some time.



Curtiss