Middle Element Blues

I've been working on various folders with triplet or tessar type lenses. Sometimes the front two elements are cemented in a single cell and come out as one. But others have the middle element mounted by itself in the shutter housing. I recently worked on a Zuiko where the middle element retaining ring had spanner holes. Oh happy day!

You'll see where this is going. I don't believe I have ever gotten a middle element free with a rubber stopper tool. I even have a set made specifically for camera lenses. The torque required for the Zuiko could never have been achieved with a friction tool. I've been lucky so far with shutters responding to lubing from the outside. I clean the back of the element by opening the aperture and setting the shutter to B. At some point I'm sure a lens will go under the drill press.

Does anyone have some trick to get these out? The alcohol thing doesn't work worth a damn.

Soak the retainer ring threads with Acetone or Acetone base Nail Polish Remover. 5 to 15 minutes is usually enough. Apply with a cotton swab.
On severe cases I have applied penetrating oil to the threads and left it to work overnight. I tear down the shutter and clean it so the oil does not cause problems.

I will have to give acetone a try. My usual go-to for loosening stuck bits, lighter fluid, doesn't help with these rings. I have always shied away from penetrating oil in case the thing refused to come apart to get it cleaned out.

At least with this last one, a Klio with a Zeiss Novar, it looks like the entire shutter can be disassembled with the middle element in place. I'm not going to try it as it is now working well enough to be a user. 1/2 and 1 second speeds are a bit iffy, but it is highly doubtful this camera would ever be used at those settings.

I just couldn't sleep at night without all the speeds being right. So I took the camera apart again and stripped the shutter down to expose the works. The middle element was still in place. Soaked it for two days in lighter fluid and the middle element still won't budge. Fortunately, it doesn't have to.. The shutter is as snappy now as when it was new and that's what matters.