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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> >
> >
> >
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