9cm elmar repair advice/rusted stuck

[ktran]

Hi Everyone,

I've recently come across a 9cm black brassed Elmar in very rough shape, and I'm trying to get it taken apart to clean the optics/etc. However, the problem is that I can't even move the aperture ring, nor loosen any of the screws (I fear damaging the heads if I apply too much force).

I suspect everything's just rusted shut, but would welcome any opinions on what/how to try getting things loosened up (general advice on disassembly is also appreciated!)

To-date, I've tried applying a bit of naphtha around the aperture ring, asking a watchmaker acquaintance to use his ultrasonic bath to see if that might work, and finally, with the knowledge that I'll be stripping and cleaning everything anyways, WD-40. So far, nothing has worked, and the aperture ring is still stuck. I've even tried unscrewing the back element out with spanners, but that's stuck too.

I'm tempted to just soak the bloody thing in naphtha, optics and all, but I will listen to Voices of Reason 🙂


Thanks in advance!

 

[ZorkiKat]

The lighter fluid trick worked for me on a lot of lenses with frozen aperture rings or levers. One of them was even a 9cm Elmar lens block, exactly like yours.

Did you use a syringe to apply the lighter fluid? You'd need to put in a rather generous amount. The aperture ring loosened and turned freely. The lighter fluid was applied 8 years ago, and the lens's aperture ring still turns freely now.

Stay clear of WD 40. It's hard to remove if it get to the blades and, eventually, on the lenses.

Also, make sure you don't upset the retainers which hold the aperture blades in place. It's no fun putting them back. I spent four days doing that.

 

[ktran]

Thanks for the insight. Yes, I'll mind the aperture blade assembly. I once reassembled an old 3-element lens with 6 aperture blades, and that was an exercise. I lose count every time I try to look at the blades in this one!

I don't have a syringe, but the ronsonol bottle has a fine drop applicator, and I'd used quite a bit, I thought. I can always try more...

 

[John Shriver]

You also should file a screwdriver to exactly the right size for each screwhead. That's how you avoid destroying them.

 

[ktran]

1 week soaking in Liquid Wrench, and still no movement... This may call for Drastic Measures...

 

[Alpacaman]

I freed up a J8 using meths once - I don't know what effects it may have no the lens though, I only soaked the stuck focusing helical. I soaked it overnight, took it out, put in back in for a few days, and then it world with a bit of force. That was dried up grease on that though, not rust. Anyone know if this is worth a try on this here elmar?

 

[Phil_F_NM]

Maybe soak in coca-cola? You'll have to take apart the aperture assembly anyways at this point, so you might as well just go all-out with the big guns. I've gotten some crazy stuck things free with coca-cola. Just don't let it sit too long... You'll wind up with a few lens elements and no barrel.

Phil Forrest

 

[_goodtimez]

Could unfreeze with ultrasonic cleaning, but I've never tried on a lens and that would mean a complete disassembly after that.

 

[sevo]

If the lens is stuck for good all you can do is saw it apart to salvage the glass and parts of the aperture as spare parts - or find some sucker to pass it on to as "vintage". If you aren't into the latter, there is nothing to lose by soaking it, as long as you do not soak it in substances that will damage the glass or metal.

 

[Ronald M]

Kroil is profesional rust buster in the engineering world.

 

[Luddite Frank]

Try putting it in a ziploc bag and placing in the freezer for a day or so, then bring it back out and try manipulating... the combination of solvent and termal contraction / expansion might break things free...

I don't think I'd try coca-cola on fine machinery... any residue left behind will come back to haunt you.

Do you have the lens barrel as well ?

 

[jmel]

more elmar

more elmar

Finally could it dismantle the Elmar?

Might he say to me how did it do it?

I have an equal Elmar to his and want to clean the interior lenses and I not know :bang:

 

[ktran]

I actually did ask a watchmaker acquaintance to use his ultrasonic bath to try to unstick the lens, but, sadly, and befuddlingly, no dice.

I ended up returning the lens for credit towards a better-condition one 🙂