Archived posting to the Leica Users Group, 2000/11/22

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Subject: Re: [Leica] Zeiss LTM Sonnar lens
From: "Dan Post" <dpost@triad.rr.com>
Date: Wed, 22 Nov 2000 12:15:40 -0500
References: <200011220801.AAA13319@mejac.palo-alto.ca.us> <003201c0547a$542184c0$dd66989e@demon.co.uk>

I would bet that someone other than the factory added the 'fluff' or it may
have been a tag of a cleaning cloth caught in the threads at some point!!
If it is in fairly decent shape, a CLA would probably fix the looseness- the
newer lubricants, litium greases- actually litium 'soaps' have a firm yet
constant viscosity over a wide range of temperatures, and often are used as
clock greases for that reason, and since they don't harden as some older
lubes, you might not have to have it serviced for quite a few years! From my
examination of the few junkers that I have taken apart, the clearance of the
helices seems to be rather large at first- when cleaned, and the tolerances
seem to be made large to allow for a certain amount of lubricant. Bronze
mountings, expecially the older phosphor bronze bayonets tend to be self
lubricating, but brass can gall and seize- so is always lubed. I would not
flush all the lube out of the lens for that reason- and oil is not a good
alternative as it can migrate to the glass.
The Sonnar seems to be a good cost effective alternative to a Summilux, as
is the Summarit, and it might be worth your while to spend $50 to have it
cleaned, collimated, and put in tip top shape! Check with Sherry or DAG!
Dan
 >
> BTW, I recently bought a Leica thread mount 5cm f2 retractable
> Sonnar - mechanically shabby but with clean T-coated glass. The focus
> mount was so stiff as to be unusable, so I tried a little lighter
> fluid and that started to slacken it off a bit.  The mount then
> disgorged a small fragment of what looked like black cloth, and is now
> very free (almost sloppy) to turn. I guess this was some form of
> friction-inducing material added to the mount during construction to
> take up the mechanical play.
>
> Regards,
>
> Doug Richardson
>
>

In reply to: Message from "Doug Richardson" <doug@meditor.demon.co.uk> ([Leica] Re: Persicopes (German, Brit & Sov) & Zeiss LTM Sonnar lens)