Collapsible Summicron M Helical Lubrication

[johnamazement]

I've just managed to get my hands on an optically excellent copy of this lens. I may have a delve inside the front elements at some point to sort out some very light haze (suction cup at the ready) but I really want to give the focusing helical a once over to start with as it's a bit stiff.

I'd rather not start stripping bits off willy-nilly so I'd be grateful for some pointers as none of my research has come up with a clear method of getting at it for the M version of the lens.

There are no obvious screws as per my old Summar, so do I have to get the whole collapsible barrel out first, or start undoing retaining rings?

Any advice would be much appreciated.

 

[Sonnar Brian]

As I understand it- the construction changed on the Collapsible M-Summicron. The screwmount version was easy, three visible screws come out. The M-Mount, there is a serrated ring over the focus mount. I've read that it comes off, revealing the inner workings.

or you could work some grease in it from the rear. The threads are visible at the cut-out.