Collapsible summicron ?'s

[-doomed-]

I just got a collapsible summicron , the aperture was stiff but runs smoothly after it became free its possible that it had been sitting a while. The focusing mount is stiff and kind of ratchety feeling, Is there a DIY way to smooth it out or should I have it done by someone. The glass is amazingly clean, near flawless. I'm excited to use this lense. Its a great fit on my IIIf as well.
What serial range do the radioactive summicrons fall in as well.

 

[Sonnar Brian]

The Summicrons above SN 105xxxx are not radioactive. SN 104 range is the cross-over.

I relubed mine, took the three screws out of the back of the focus mount to get the helical apart. You have to be careful of the starting position, there are multiple possible ways to start it- but only one is correct.

The lens that I relubed was a thorium lens that had been sunbleached. The heat messed with the lubricants. It is smooth as butter now.

 

[-doomed-]

Brian , I was hoping you'd chime in here. Any tips on getting the helical started correctly? Any specific lube you'd recommend?

 

[Sonnar Brian]

I use white Lithium Grease, found at a local hardware store. It is not expensive. I had been using Vacuum Pump Grease, but it is heavier. The latter is good for worn helicals.

From my last J-3 rebuild.

On getting the helical started- make some marks when taking it apart. Note carefully the starting position, and when it is at infinity and close-up. At minimum focus, the RF cam should be almost flush with the beginning of the threads. Make a scribe on the metal if you can, if you use a marker- the ink will come off when you clean off the old Lubricants.

 

[-doomed-]

White lithium grease, Ive got plenty , and I've got a small pick to mark some reference points as well. I'll get to this tomorrow. I guess I can check infinity and such with the frosted tape method on my M3 . Thanks for your help.