Help cleaning Rodenstock eurynar 4.5 36 CM

[Jay Skjonsby]

Any Suggestions would be helpful, I just received a 36cm rodenstock eurynar anastigmat brass barrel lens serial number 116501.

I can't get the front element assembly apart to clean the inner surfaces of the two elements. I tried soaking Jim's G. trick by soaking it in hot water and dish soap. But no Luck.

If you have one of these lenses or have worked on one you will probably know the answer. The front assembly is cast aluminum and there appears to be line or mark that suggests it comes apart to expose the inner element surfaces.

There is a retaining ring on the outside of the front element that looks pretty tight. I would prefer to get the assembly apart.

Greatly appreciate your help!

[Steven Tribe]

Rodenstock used the Eurynar brand on several different objective designs. The one I have worked on was a dialyt structure - two separate lens in both cells. It was easily disassembled from the inside (retaining ring, lens, spacer, lens) from the inside of each cell once these cells were removed from the barrel. A 36cm should width enough to work out a system of applying more torque on the cell threads.

[amac212]

years ago when rehabbing an old ansco 6x9 folder, I faced what seemed like am impossible problem with the lens. The manufacturer used to use this lubricant that over the decades turned into a cement. I could not even turn the focus, much less the separate elements.

I don't know if yours would benefit from my solution, but overnight submerged in lighter fluid (yes, lighter fluid) and everything moved freely. Best of luck whatever you do.

[ic-racer]

I have removed stuck lensrings by heating. What works for me is to set the lens on top of an old paper dryer at about 200F for a while. The heat expands the barrel and the lensring will unscrew.

[Jay Skjonsby]

Thanks everyone all good comments. It is a pretty good sized lens. I think I am going to try the hot water soap one more time. And give it a little extra torque with the oil filter wrenches and rubber spacer.

If that does not work I can go for the overnight in lighter fluid. I have used lighter fluid for alot of my cleaning jobs but never soaked anything in it but I have heard alot of people do with great success.

Thanks everyone!

[E. von Hoegh]

Penetrating oil; that is: Kroil, PB Blaster, Liquid Wrench, even #2 heating oil.

Gently warm the item, then put a dab of penetrant on the seam. Repeat. Repeat some more. With patience, most things loosen. If you have aluminium screwed into brass, chill the item before trying to loosen.

[cdholden]

Penetrating oil; that is: Kroil, PB Blaster, Liquid Wrench, even #2 heating oil.

Gently warm the item, then put a dab of penetrant on the seam. Repeat. Repeat some more. With patience, most things loosen. If you have aluminium screwed into brass, chill the item before trying to loosen.

I can't speak for the others but PB Blaster is a very strong solvent. I would be cautious if you care about the possibilty of brass lacquer being removed. If you only want function, go for it. PB does wonders on corroded bolts.

[E. von Hoegh]

Oops! I didn't even think about the solvent factor. Any will work, the most important tool is patience.