Can you help me get this lens cell apart

[jim10219]

I've got that exact same lens. I had some fogging between those two elements on mine, and I ran into the same road block you did when I tried to separate them. What I eventually did was dipped a Q-Tip in some solvent and ran that around the edge and let it soak in between the grooves, then it popped right out. It appears the front element is glued down. I can't remember which solvent I used, but it was probably rubbing alcohol or naphtha.

[paulbarden]

I've got that exact same lens. I had some fogging between those two elements on mine, and I ran into the same road block you did when I tried to separate them. What I eventually did was dipped a Q-Tip in some solvent and ran that around the edge and let it soak in between the grooves, then it popped right out. It appears the front element is glued down. I can't remember which solvent I used, but it was probably rubbing alcohol or naphtha.

And if those solvents don't work, try Acetone.

[williaty]

This is an unfortunate back entry job.
The two lenses and spacer have been loaded from the rear and the brass tube has been lathe burnished (Friction causing the brass to become plastic)to create a thin retaining overlap.
This system was cheaper in terms of labour costs than making threads and screw rings. The lenses were never expected to be in use more than a dozen years, or so!

Took me a while to get back to this.

Side image of the lens cell:



I'm trying to upload a video to Youtube that shows the construction much better but it appears that the upload function is currently broken.

[williaty]

Youtube still seems broken but I uploaded it to Gfycat:

https://gfycat.com/AnchoredDisfiguredLamprey

[Steven Tribe]

Super video!
Yes it is mounted from the back. Somewhere underneath the black enamel covering the edge of the rear lens, is a brass edge. Perhaps not burnished, but with the black paint acting as a sealant/glue? This would explain the solvent/push out solution mentioned in one of the last posts. It may have already received this treatment a couple of times, as air spaces do get soiled over time.

I would:

1. find out where the brass ends and the lens begins under the black paint.
2. is there a burnished edge over the glass?
3a. if there is an edge, then mechanically bend back the edge.
3b. if just a friction fit, sealed with paint - go to 4!
4. remove as much of the paint layer as possible mechanically! excess solvents are not good!
5. push the lenses carefully through the rear.

[c.d.ewen]

Steve:

I have to cautiously disagree with you. Here are my two reasons for thinking that the cell comes apart by unscrewing the front: knurling, in my experience, is rarely decorative; it's meant to indicate a part that unscrews. Also, if the rear of the cell is opened, can the front element fit through it?

I have several similar Tessars, and will try to find some time to experiment with them.

Charley

[Steven Tribe]

It is certainly possible, but I have seen knurling that has no function - other than decoration.

The rear lens seems to hang out of the back showing a lot of the lens edge. I assume that the black paint covers almost all of the lens edge and that the brass rim is quite narrow. There is an overlap of this brass which can be seen at the top.
Perhaps an oversize front lens is permanently and separately mounted in the front. But cleaning would be possiblle with just the rear lens out.

[c.d.ewen]

Sorry to report no progress. Spent too much time at the ER getting staples in a minor scalp wound. Maybe tomorrow.

Charley

[pepeguitarra]

There's always a hint - see the knurling on the top of the piece holding the beauty ring in? Get yourself a big rubber stopper or something else to get some friction on that ring and start turning. There are marks in the knurling at 10 and 1 o'clock. I can't tell if they're notches for a lens wrench or not. Check it out. If there are notches at 180 degrees, you've got your answer.

Charley

I have nothing to add here, only that by reading this comment, I remember that I have a Convertible Schneider 50/5.6 -214/12.5 that I could not remove for months. After reading this, I recalled I have some of those rubber stoppers that I used to clean the lenses, and put one around the rim of the front element, and after some hard trying, I was able to unscrew it. It pays to read all the comments. Thanks.

[pepeguitarra]

And if those solvents don't work, try Acetone.

Thanks, Acetone dissolves Crazy Glue. Which I am going to try now. I have a piece or adapter that someone glued (?) on a Copal 1 shutter and I have not been able to remove it, even after dropping some wd40. I now realize that it may have been glued. I will get the acetone to try. Thanks.