Thank you, Barry. This is what I suspected (feared?) In fact, it is
possible to buy metal foils in narrow widths and about =.0001 inch thick,
but they will be rather expensive and I doubt if they will be appearing in
hobby shops. However, if somebody really has a source of inexpensive
material covering the range from 0.0001 to 0.0005, it would be
wonderful. Unfortunately, except for 0.0005 (which I can get here, as a
rough metric approximation), the only sources I know are specialists for
scientific raw materials and the prices might be a turn-off. To be a
little more concrete, I have a catalog in front of me, and there I find
various metals (brass, stainless steel and many others) at about $75 to
$100 for a piece 25 mm x 25mm (1 inch x 1 inch). This is for material 5
microns (0.0002 inch thick). At 12.5 microns thick the price drops by 30%
or so. In selected, pure metals less than 0.0001 inch is
possible; tantalum is offered at 1.5 microns and $150 for 25 mm x 25
mm. (Tantalum is a wonderful metal to work.) This thickness is just a few
wavelengths of light (roughly 3 wavelengths for light in the middle of the
visible spectrum)
However, take Barry's advice, you hardly need such thin material for a
pinhole. Furthermore, if you make the hole and then rub the finished
product on a fine sharpening stone (India), and press correctly (try a
finger over the hole) you can thin the foil locally, with the fastest
thinning at the edge of the hole. You then have support by stronger, outer
material and a thinner pinhole. Observe frequently with a microscope to
know when you about to go too far!
Incidentally, if you do go for the thinnest foils, you can make a lot of
pinholes for your money so it may not be a bad investment. Just glue a 5
mm x 5 mm piece with the hole over a thicker foil with a larger (2 mm ?)
hole. You would be getting 25 such holes for your $100.00 and nobody says
you can't make still smaller chunks from your thin foil, getting the cost
under $1.00 per hole. (I leave it to you to decide what to do with 100
pinholes in very thin foil.)
Bob
At 15:52 20.09.01 -0700, you wrote:
I am a machinist. We use shim stock all day long. The
thinnest shim we have been able to find is .0005 which
is half a thousandth or five ten thousandths. We
(Boeing) have not been able to find shim in .0001. But
then, it woulkd be so weak it would tear when you
drilled it. .001 works teriffic. I have used up to
.002 with success. It is best if you drill a smaller
hole with a needle then knock the burr off the other
side with sandpaper, drill larger, deburr and go to
final size. The thinned the shim material is at the
edge of the hole the less diffraction problems you
will have.
Barry
--- Robert Stoddard [EMAIL PROTECTED] wrote:
Do you guys really mean one ten-thousandth of an
inch shim stock? Can you
possibly mean one thousandth of an inch (i.e.,
0.001)? RKS
From: Guillermo [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Cameramakers] Re: pinhole camera
Date: Thu, 20 Sep 2001 16:18:49 -0400
RE: [Cameramakers] Re: pinhole camera
- Original Message -
From: J. Poutasse
To: '[EMAIL PROTECTED]'
Is it really possible to buy shim stock 0.0001
to 0.0005 at hobby shops
in
the USA?
I've bought it in little packages with sheets of
varying thicknesses at
an
auto
parts store. It wasn't very expensive as I
recall. One package will make
lots
of cameras. Jackie
Jackie, I doubt you got any 0.0001 to 0.0005 in the
package you bought. I
believe that the thinnest one available is 0.0005.
Bob, I will check if my supplier here in Canada has
or is able to order
0.0005, if so and you are interested in that
thickness, I wouldn't mind
buying it and sending it to you. I will contact
you off list.
Guillermo
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