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.

[alps-art.ch]

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

"Righty-tighty, lefty-loosey"

Yes, counter-clock-wise looking from the ring's side.. thanks.

[E. von Hoegh]

Acetone will dissolve superglue. Methyl ethyl ketone will dissolve many other glues, even some epoxies.

Try putting the lens in the freezer overnight, then hold the tip of your soldering iron againt it.

[lenser]

Two things: One, after removing all glass, do the whack, but at quite a few points around the ring. It could be one very tiny point that is corroded and sticking and the concussion needs to find that point.

Second, consider buying a strap wrench for the shutter assembly. Those usually have a fairly soft band that snugs around the item to be loosened and then gets much tighter as you apply force. A strap wrench applies even force (much more even that the human hand) around the circular object (shutter) so that again, any one small sticking point can be broken free.

Good luck.

[E. von Hoegh]

Two things: One, after removing all glass, do the whack, but at quite a few points around the ring. It could be one very tiny point that is corroded and sticking and the concussion needs to find that point.

Second, consider buying a strap wrench for the shutter assembly. Those usually have a fairly soft band that snugs around the item to be loosened and then gets much tighter as you apply force. A strap wrench applies even force (much more even that the human hand) around the circular object (shutter) so that again, any one small sticking point can be broken free.

Good luck.

The handle of the strap wrench applies high pressure to whatever you are turning, maybe not a good idea.

"Whacking" on the shutter can easily convert a good but stuck shutter into a free but ruined shutter. Give a series of very light taps all around the ring.

[alps-art.ch]

Second, consider buying a strap wrench for the shutter assembly. Those usually have a fairly soft band that snugs around the item to be loosened and then gets much tighter as you apply force. A strap wrench applies even force (much more even that the human hand) around the circular object (shutter) so that again, any one small sticking point can be broken free.

Is that large hose clamp described in

http://www.largeformatphotography.info/forum/showthread.php?t=79786

what you mean as "strap wrench"?

[Jon Shiu]

You can also use the brute force method of using a large wrench to turn your lens wrench. This may break/bend the lens wrench, though.

If there is a anti-rotation pin coming out of the back of the shutter, you don't want to try to turn the shutter.

Jon

[alps-art.ch]

Acetone will dissolve superglue. Methyl ethyl ketone will dissolve many other glues, even some epoxies.

Thanks, I shall try pure acetone, perhaps glue (if it is there) will at least thicken and lose its strength. What about tetrahydrofuran (THF)? It is a popular solvent in chemical labs for polymerized staff..

[Brian C. Miller]

Don't apply any force to the shutter side, unless the shutter is moving when you move the retaining ring.

If the cooling-heating cycle didn't do anything, then it could be possible that the threads themselves are jammed, prior to being completely stripped, and nothing will mechanically remove that ring. For a last-ditch effort I would contact SK Grimes and ask if they can remove the ring. They probably have a tool specifically for extremely stuck rings.

[alps-art.ch]

You can also use the brute force method of using a large wrench to turn your lens wrench. This may break/bend the lens wrench, though.

If there is a anti-rotation pin coming out of the back of the shutter, you don't want to try to turn the shutter.

Jon

Well, it is not an easy exercise to put a lot of force while keeping a wrench tool exactly at the right position.... I think I already did my best using brute force only. The German-made tool did survive it, though :)

There is no blocking pin. I can see a distinct clearance between the lensboard and the surface of the shutter, including the threaded central brass tube.

[Alan Gales]

We have an automotive product in the United States called PB Plaster. You spray the stuck nut and bolt and then wait up to a day and then remove them. It works great.

It it is not glued but merely over tightened or cross threaded perhaps there is a similar product in Switzerland that you could try.

Good luck to you!

[Alan Gales]

Sorry. That's PB Blaster!

[c.d.ewen]

+1 on the PB Blaster. I was told the local shipbuilders (big saltwater craft) keep a supply on hand for corroded nuts.

Have you considered cutting away to lensboard?

Charley

[domaz]

When all else fails you have to do something drastic. I think it's time to get the Dremel out. Cutting away the lensboard seems like a good idea. You could also directly cut the retaining ring with the Dremel but that is risky as it would be easy to go to far and cut the threads of the shutter.

[alps-art.ch]

Have you considered cutting away to lensboard?
Charley

As the last mean, yes. But rather break the retaining ring. How one can cut away lensboard?

[alps-art.ch]

When all else fails you have to do something drastic. I think it's time to get the Dremel out. Cutting away the lensboard seems like a good idea. You could also directly cut the retaining ring with the Dremel but that is risky as it would be easy to go to far and cut the threads of the shutter.

I poked Dremel website, there are at least 4 tools - Rotary, Multi-Max, Trio, Saw-Max. Which one of Dremel tools did you mean?

[c.d.ewen]

Dimitri:

What's the lensboard made of? Wood? Metal?

Charley

[alps-art.ch]

What's the lensboard made of? Wood? Metal?


Metal, a kind of aluminium alloy

[bobwysiwyg]

You would need a second set of hands, and possibly end up sacrificing a wood chisel, but you can hold the chisel at an oblique angle to the ring to get a bight, and give it a shot with a light hammer, obviously in the direction of unscrewing. Best done hitting downward with the board edge on a bench with someone holding the board perpendicular to the bench. If it works, there might be a slight nick in the ring, but...

[cyrus]

Wow this retaining ring is turning into quite a saga, huh!

[alps-art.ch]

You would need a second set of hands, and possibly end up sacrificing a wood chisel, but you can hold the chisel at an oblique angle to the ring to get a bight, and give it a shot with a light hammer, obviously in the direction of unscrewing. Best done hitting downward with the board edge on a bench with someone holding the board perpendicular to the bench. If it works, there might be a slight nick in the ring, but...

Yes, I see what you mean... but I am still hoping to accomplish without drastic exercises :)

[alps-art.ch]

Wow this retaining ring is turning into quite a saga, huh!

I really hope all these might be useful not only for myself... kind of common problem..

[c.d.ewen]

I really hope all these might be useful not only for myself... kind of common problem..

Quite true. I search the archives all the time for solutions,

Also, this thead is long because you've taken an admirably conservation approach.

RE: Dremels. You need a rotary dremel (don't get a battery powered one - too weak). You can get a package (20 in a tube) of things called "cutoff wheels", which are small abrasive disks. They are terribly messy - throwing abrasive dust everywhere, and they're easily broken if twisted. You must wear eye protection. They're for small jobs, e.g., cutting a retaining ring, and not really for bigger jobs, like cutting up a lensboard. You can do it, but you need a lot of patience, and a lot of cutoff wheels.

One last thing to ponder and worry about: galvanic corrosion. What this means is that metal parts can weld themselves together over time. Aluminum near salt water will do this fairly rapidly. It's possible to cut away the lensboard and expose the retaining ring, then carefully cut the ring, only to find that the ring will not pull away from the shutter without taking chunks of the shutter's threads.

Life's never easy, but everybody gets lucky spmetimes.

Charley

[Steven Tribe]

If you have a reserve ring than the time has come to either hacksaw or bore the damn ring and break it with a scrap screwdriver. Any damage to the thread will have no consequences. It will have to be thoroughly cleaned anyway.

[c.d.ewen]

Yes, it's time to take the advice of the drill sargeants I had in basic training. To keep us from freezing out of indecision, they'd yell: "Do something, even if it's wrong".

Charley

[bobwysiwyg]

Alps, should we assume none of these possible solutions have worked thus far?

[alps-art.ch]

Yupee, VICTORY!

How it was done:
0. Removed both front and back lens halves
1. The lensboard+shutter kept in cold (about -1 Celsius) for about 1 day
2. The retaining ring was heated up by soldering iron (5 min) in several points till it become warm (not hot)
3. A second person was holding the lensboard (with gloves worn), while I took a wrench tool using pliers in both hands, aligned the wrench against ring notches, and put some (not really brute) force. Bingo!

Neither ring (an aluminium alloy) nor shutter's central tube (brass) were corroded. No traces of glue either.

Hard to say what made decisive contribution. IMHO:
1. cold + warmth, as usually
2. A pair of pliers really armed me

Thanks a lot for you all, for you ideas and support! Although I have not try each idea suggested, they helped me to take an apparently right approach.

THANKS!
Dimitri.

[bobwysiwyg]

Congratulations! Success is sweet. :)

[rdenney]

Glad it worked out.

I have not reviewed this thread until now, and just for future interest:

1. Kroil is better than PB-Blaster. But a mixture of oil and acetone is better than either. The old trick in restoration circles is a mix of transmission fluid and acetone--transmission fluid is a moderately light oil and any such would work. But these work against certain types of corrosion. They don't work for some galvanic corrosion and they won't soften all glues.

2. A good tool for whacking is a rawhide hammer. Musical-instrument repair technicians use these for unsticking threaded connections that have corroded a bit. A small rawhide or phenolic hammer will do much less surface damage than a metal hammer. Glancing blows in the direction of unscrewing at various points around the ring will often do the trick.

3. For cutting it away, I would use a burr grinder, which, unlike a cut-off wheel, will get down into the corner between the threaded barrel and the backside of the lens board. It's okay if you grind away a bit of the threads on the shutter--just don't grind through the barrel. A burr grinder only needs to be a sixteenth of an inch wide--1 or 2 mm--and fits in a Dremel as described for the cut-off wheel. Just plow out a gap into the ring. Then, one can use a wedge (i.e., screwdriver) to apply a twisting pry force to spread the gap. That should break it loose easily. Of course, the retaining ring will have to be replaced after that.

4. I have used a tiny dab of anti-seize lubricant on the threads of aluminum shutter threaded barrels before applying the retaining ring, to prevent getting stuck in the future.

Rick "just some comments for posterity" Denney

[bobwysiwyg]

4. I have used a tiny dab of anti-seize lubricant on the threads of aluminum shutter threaded barrels before applying the retaining ring, to prevent getting stuck in the future.


Whether camera or not, this is very good advise if you are bringing dissimilar metals together.

[c.d.ewen]

Dimitri:

Congratulations! The simple, old methods are often the most reliable.

Rick:

Is Kroil somehow a regional product? I've never seen it on a shelf, and I've prowled every hardware store in the county. Thanks for reminding me about the ATF+acetone. I've got a stuck beauty ring that's resisted all efforts.

Charley

[alps-art.ch]

Charley, bobwysiwyg, Rick and all in this thread - thanks again! I am really touched by your participation and attention to my problem.

-- Dimitri.

[rdenney]

Is Kroil somehow a regional product? I've never seen it on a shelf, and I've prowled every hardware store in the county.

It's rare to find it on the retail shelf. I buy it by the case directly from Kano Labs, the manufacturer. I have plenty of uses for it out here. They also sell instrument lubricants very useful for camera tinkerers (Microil).

Rick "http://www.kanolabs.com (http://www.kanolabs.com/)/" Denney

[cyrus]

Ok so anyone else wants something unstuck? Cuz after 43 posts, we can unstick anything!

[c.d.ewen]

Ok so anyone else wants something unstuck? Cuz after 43 posts, we can unstick anything!

Not quite, Cyrus. We didn't get into my plans for that beauty ring. Plans which involve the usage of a 24" pipe wrench :eek: If only I could locate some Kroil!

Charley (who only has one sig name, and thus can only end his posts half as well as Rick () Denney)

[henseman]

Hi Jon,

Found this article while trying to remove a Schneider Super Angulon f:5.6/90mm lens from a Linhof lensboard and was wondering if you were familiar with this lens and whether I had an anti rotation pin to worry about?

(Added)

I forgot to mention that it is in Syncro Compur shutter, if that makes a difference.


You can also use the brute force method of using a large wrench to turn your lens wrench. This may break/bend the lens wrench, though.

If there is a anti-rotation pin coming out of the back of the shutter, you don't want to try to turn the shutter.

Jon

[Jon Shiu]

Yes, they sometimes do have the pin.

Jon

Hi Jon,

Found this article while trying to remove a Schneider Super Angulon f:5.6/90mm lens from a Linhof lensboard and was wondering if you were familiar with this lens and whether I had an anti rotation pin to worry about?

(Added)

I forgot to mention that it is in Syncro Compur shutter, if that makes a difference.