First Foray Into The Pinhole

[Christopher Walrath]

I used the tip of a small sewing needle. Aperture with the 11mm f/l is about f90 or so.

[Christopher Walrath]

Oh, and to avoid tin foil rolling up inside the box as a result of the puncture, I rolled the needle back and forth in my fingers until it just finally pierced the foil.

I'll post a pic as soon as my husbandly/fatherly duties dictate the opportunity.

[eddie gunks]

How does one make such a small pinhole? I am thinking of making one of these today!

- Justin

you can use small hobby drill too. i began using them with great success. google up the sizes. i forget off the top of my head.

eddie

[Greg_E]

http://www.smallparts.com has number drills. The sizes are listed in a chart, and you will probably want a number higher than about #60. The higher the number, the smaller the hole.

[DWThomas]

The smallest drill you are likely to find is a number 80 which is 0.0135 inches/0.3429 mm in diameter -- and pretty scary to work with! The other problem with drills is they may not leave a clean edge, especially unless you have some sort of high speed precision drill press to use them in. Many normal sized drill chucks can't even grip drills that small. I have used a pin vise chucked in a larger drill press but there's little sensitivity to tell how hard it's being loaded.

In theory, pushing a bump into thin stock with a needle, then sanding in a circular pattern with extremely fine sandpaper can create a relatively clean hole with a knife edge, a sort of optimum optical situation. And of course, it is about as inexpensive as you can get.

I used to have some of those very small drills (some in solid carbide even) for use on circuit boards, but most long ago went the way of tiny fragile things spinning at high speeds under less than ideal conditions.

DaveT

[Greg_E]

Small parts has expensive stepped versions of the number drills with a much larger shank. But much smaller than a #80 would be really difficult.