turner-reich 12" convertable antastigmat fungus removal

[lloyd goode]

i can not figure out how to remove lens cells from the barrel so i can clean between the elements. Are they glued in? No apparent slots for the wrench that I can find. .Any help would be greatly app.reciated.

[Ron in Arcata California]

TR convertible lenses do not have air spaced elements. As well the lenses are held in place by rolling the brass rim down on end facing inward. The rim is not easily removed but can be done in a lathe. I have re-cemented TR lenses but it ain't easy.

[Don Dudenbostel]

It’s a tricky procedure to do this. About 45 years ago I had a neighbor that was a precision machinist and specialty optical builder for the department of energy. He designed optical systems out of non browning glass to be used in high radiation environments such as inspecting experiments running in the core of nuclear reactors.

My Turner Reich convertible like virtuall all the others had balsam crystallization in both cells. My friend successfully removed the cells but while slowly heating the cell to soften the balsam one element cracked.

I think some people have had success getting the elements apart soaking the cell in acetone and other solvents for a week or so so it might be easier and less risky that way. Once you’ve gotten them apart you have to get the cell back together in alignment. I believe there are 4 elements per cell which makes reassembly properly very difficult.

[Nodda Duma]

Turner Reich Anastigmats are 10 elements in 2 groups. Kind of like a Dagor, but two additional pieces of glass bonded on to get around the Dagor design patent and still provide similar level of correction (hence 5 elements per group instead of 4). On earlier TRA’s, the barrels are turned down ie burnished to retain the lenses on the ends closest to the shutter. Post-WW2 or WW2 era lenses (not sure when) changed to threaded retainers.

To remove the glass, the burnished part of the barrel has to be cut away carefully on a lathe. Then the lens can be pushed out and serviced. The burr on the cut metal treated with a chamfering tool to allow easy replacement of the repaired lens. If done right, the cut away burnished ring can be kept and reused, the cut away metal replaced with epoxy.

I’ve restored quite a few of these, like this one which was totally occluded by balsam separation.

[Michael Roberts]

Woo Pig! That is some beautiful glass!

[lloyd goode]

Thanks for all the information and the drawing. Now I need to figure out if what I thought was fungus is really balsam crystallization. I can probably live with crystallization, not fungus.

[Nodda Duma]

Thanks for all the information and the drawing. Now I need to figure out if what I thought was fungus is really balsam crystallization. I can probably live with crystallization, not fungus.

Knowing that lens it’s likely balsam. They almost universally suffer from it. If you post a good picture I can tell you pretty quick.

[lloyd goode]

hard to get a good picture of what is going on.

[Nodda Duma]

hard to get a good picture of what is going on.

The “flower” looks like a speck of dust was trapped in the balsam layer when first cemented, causing separation over time. Balsam separation and oxidation at the edge.

[lloyd goode]

Thanks again for the evaluation. I was scared it was fungus that might creep into my other lenses.