How to unscrew a stuck retaining ring?

[alps-art.ch]

Hi,

I purchased a used 210mm Symmar S in Prontor#1 mounted on a Horseman lensboard, hence I need change it to my Toyo 45AX board. The retaining ring appears dead stuck.

I have tried to soak its thread with some white-spirit, then some paint-dissolver (containing aceton), then lubricated with a drop of machine oil, left it for few hours, then used a Linos wrench tool to unscrew. I applied all my force with two hands (while other person was holding the lensboard with the lens) -- no way.

Anybody can suggest a trick?

Thanks,
Dimitri.

[Jim Noel]

Perhaps the ring is super glued to the board. Have you tried turning the shutter rather than the ring?

[cyrus]

You can try somehow selectively heating the retainer ring, make it expand, thus making it easier to remove?

[alps-art.ch]

Perhaps the ring is super glued to the board. Have you tried turning the shutter rather than the ring?

Yes, I have tried to turn the shutter (with all my force reasonable to apply onto such a weak construction) -- no visible rotation. I also afraid it is glued.

Should I try heat the ring with a touch of soldering tool? Perhaps, that will burn glue?

Thanks,

[alps-art.ch]

You can try somehow selectively heating the retainer ring, make it expand, thus making it easier to remove?

Great, it must be reading of thoughts... just wrote that myself

[cyrus]

Great, it must reading of thoughts... just wrote that myself

But I never thought of the soldering tool.

Also, a good whack often loosens tight jar lids...

[c.d.ewen]

Before applying heat, you might try putting it into the freezer. If it happens that the ring is glued, and glued with superglue, you might get lucky. Superglue doesn't hold well at freezing temperatures.

Charley

[alps-art.ch]

Also, a good whack often loosens tight jar lids...

Surely yes, just will unscrew the remaining half of the lens beforehand

[cyrus]

PS not to state the obvious but are you sure you're turning it the right way?

"Righty-tighty, lefty-loosey"

[alps-art.ch]

Superglue doesn't hold well at freezing temperatures.

Actually, not a bad idea... stones get cracked because of temperature cycles... thanks.