1937 Agfa Jsolette Jgestar front cell setscrews/dogscrews?

I picked up an Agfa Jsolette dual format (6x6, 6x4.5) camera...probably 1937.

The front lens cell distance scale setscrews/dog screws have chewed up slots, so they cannot be tightened. The dried grease in the lens cell threads has been removed, so the lens can focus, but the distance scale can't be tightened so the scale ring cannot rotate the focusing cell.

How does one go about identifying characteristics for such tiny screws, in order to seek replacements?

Thanks

Murray

How does one go about identifying characteristics for such tiny screws, in order to seek replacements?

Are you asking how to measure and specify screws that you have in hand? Or do you mean something different?

You might check this site to see if they have what you need.

Miniature Screws | NBK | Couplings, Screws, Clampers

I picked up an Agfa Jsolette dual format (6x6, 6x4.5) camera...probably 1937.

 

The front lens cell distance scale setscrews/dog screws have chewed up slots, so they cannot be tightened. The dried grease in the lens cell threads has been removed, so the lens can focus, but the distance scale can't be tightened so the scale ring cannot rotate the focusing cell.

 

How does one go about identifying characteristics for such tiny screws, in order to seek replacements?

 

Thanks

 

Murray

So, how did you get the glue... I mean grease to let go enough so that you could get the lens apart? I have the same camera.

These screws might be too small for this to work but I've heard of people using a dremel and a cutting wheel to "re-slot" screws, - basically they bring the wheel down perpendicular to the top of the screw and cut another slot or cut a deeper slot where the current one is (or was).

I must have notifications disabled...not ignoring you guys.

On other Agfa's I have used a hairdryer if I had the lens/shutter off. Most of my others had unsalvageable bellows. This one has only a few light leaks (for the time being). I think I was nervous about heat near the bellows and put a couple drops of anhydrous isopropyl alcohol on the threads.

Or everything I did was for naught because the previous owner did it & the inability to focus was actually the stripped grub screw heads.

With the scale ring off I am able to unscrew the front cell...or what I am able to remove is actually the front + middle. With a piece of ground glass in the back, I really don't see a sharp focus wide open, screwing the lens all the way in or out.. so I wonder what else is goofy on this. I assumed it was my eyesight but a quick check with a Kodak 35RF is easy to observe sharp focus. I suppose these are probably all air-spaced & potentially the front cell is still stuck to the middle one. I think I should have been able to focus on something somewhere if it's complete...it's close so probably not missing an element.

I did pick & poke the chewed slotted grub screws out, put them into a pin vise one at a time & measured the major diameter as 1.44 mm so I'm calling them M1.4. they seem to be between 3.5 & 4.5 mm long but that's including the cone point & guessing how much is missing.

I filed 2 of the 3 flat for the sake of attempting prepping for slotting but am not sure what I can accomplish myself. I didn't think about Dremel. I had ruled out razor saw (for me) someone had suggested. I left one as-is in case it reveals anything useful.

I might have found some M1.4x3 which is better than nothing.

TBD why the focus is indistinct. Lens is clear.

I think what I found were JIS M1.4x4, and they fit OK.

The lens focuses about 1/4" behind the film plane, so I can only guess a prior owner put a lens element in backward...they can't be out of order.

I think what I found were JIS M1.4x4, and they fit OK.

 

The lens focuses about 1/4" behind the film plane, so I can only guess a prior owner put a lens element in backward...they can't be out of order.

Are you able to get the front two elements apart? The distance between the front two elements is what controls the focus and they are often frozen in time on these old Isolettes and won't budge.

Recently I was able to get one pair apart by soaking them in a heated denatured alcohol bath. It took about an hour and a half of soaking. Other solvents like naphtha would probably work as well. Put the elements in a jar (or some small container) with the solvent. Set the container in a pot of hot water on a stove. I kept it well below boiling but plenty hot.

I checked on them every 15 minutes or so. I could start to see the old grease leach out before long. And eventually I was able to spin the elements apart.

Thank you.

Been a while so I don't recall, but think I had no trouble, which surprised me...previous owner may have unglued it. I got shutter running reasonably & also found the bellows to have minimal holes (pre-war materials some believe to be more durable than later ones), so temporarily patched with black photo tape until it proves itself worth a new bellows.

I will examine the lens cells for surprises.

Thank you.

 

Been a while so I don't recall, but think I had no trouble, which surprised me...previous owner may have unglued it. I got shutter running reasonably & also found the bellows to have minimal holes (pre-war materials some believe to be more durable than later ones), so temporarily patched with black photo tape until it proves itself worth a new bellows.

 

I will examine the lens cells for surprises.

I have a pre-war model as well and I was surprise that the bellows was fine, - no leaks. And that's a very good thing because there doesn't seem to be an easy way to remove it from the body of the camera, - at least on mine. The metal frame holding it in place seems to be spot welded rather than mounted with screws.