Cleaning focussing helical, Summicron 50 v5 - any tips?

[Jonathan R]

Focussing helical has become jerky at the infinity end. I am handy at this kind of thing, have the necessary tools, and don't want to send the lens away. From YT videos, I understand that a single lock ring separates the lens unit from the focussing mechanism, and I assume the rest is obvious. Is there anything else I need to know before I start this, please?

What grade of grease should I use? Should it be damping, or just a medium grade?

 

[santino]

I‘ve been told that synthetic grease people use for telescopes is ideal. Medium grade seems to be right, I don‘t think that a Leica helicoid has worn to a degree that there is play.

 

[Freakscene]

Soft or medium Helicoid Lube: Helicoid Lube+ Damper Grease for Lenses & Cameras or Klüber Catenera 8.

 

[Duofold RF]

Helicoid Grease for Camera lens Made in Japan

Very High lubricating performance and heat /cold resistance! Helicoid Grease is a special synthetic oil that meets tough demands, such as those regarding lubricity, cold and heat resistance, minimal leakage, and harmlessness to resins.Please use it on optical instruments, such as camera lenses...

japanhobbytool.com

They have different grade damper

 

[Jonathan R]

Thank you, everyone. I’ll tackle it this afternoon.

 

[Jonathan R]

Well, that wasn't too hard. I marked everything before disassembly so that it could be aligned again the same way, and strongly advise anyone else to do the same. The helical itself was much shorter than I expected, and VERY fiddly to re-engage once separated. I used the Medium grade Japanese grease that @Duofold RF linked to, because I already had it. It has a reputation for separating out, but the original lube had done exactly that anyway. I cleaned everything and used only a trace of fresh lube. My starting situation was that focussing near infinity had become sticky, almost a click, which quite took the pleasure out of using the rangefinder. Now the whole focus movement is super smooth again.

There was a 2007 thread on the subject here on Rangefinder Forum, in which folk seemed to expect these focussing movements to be Leica-slick indefinitely, without maintenance. My lens is now 40 years old. I reckon a 40-year service interval isn't bad.