where do you purchase very small screws????

[Len Middleton]

Frank,

Thanks the photo really helps.

As you have seen on your Optar, the section of the shuuter barrel that has an internal thread to take the rear lens section, is typically threaded externally to thread a retaining ring onto.

Yours looks smooth with no external thread, which is that I have seen with oscilloscope lens shutters. In those applications, the shutter was held in place with a clamp and certainly there are a number of suggestions here on how to fix that.

I do not know why they clamped them in on oscilloscope cameras rather than thread them in (would manufacturing costs be that different?), unless maybe the clamping also allowecd them to do a fine focus prior to tightening the lens in place...

Now you need to take a look at the aperature scale...

Good luck,

Len

[pocketfulladoubles]

Go to http://www.smallparts.com/ They're my first and usually only stop.

[pablo batt]

you will need to find a really small shop

[Robert A. Zeichner]

Check here.

[John Cahill]

Surplus Shed, near Allentown, PA is offering bags of photo-type little screws taken from Wollensaks, binocs, other optical apparatus. Google it.

[Vick Vickery]

Thats a strange shutter setup that I haven't seen before, and I have several lenses on Ilex #3 shutters. Looking at it, I think I would tend to try a tight "O"-ring first, maybe with a couple of turns of black tape over it to make sure it stays in place...cut the hole in the lensboard tight, push the extended ring on the back of the shutter thru, place the "O"-ring on, put a couple of turns of tape around to keep the ring there and seal any possible light leaks around the hole.