Archived posting to the Leica Users Group, 2006/01/12

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Subject: [Leica] Interesting problems with M39-Leica M adapter
From: don.dory at (Don Dory)
Date: Thu Jan 12 15:23:55 2006
References: <>

I would take a flat fine file and file the offending lug horizontally, in
other words take the burr off that is causing the lack of rotation.  It is
possible that whoever did he original work actually bent the lug just enough
the keep the adapter from mounting on a bayonet.  It either a burr of metal
or a bent lug so removal of a small amount of metal should do the trick.  We
are after all talking about a small amount of money even if things go
woefully wrong.


On 1/12/06, Martin Jangowski <> wrote:
> Hi folks,
> I recently bought a CV adapter ring M39-Leica M. The seller said it was
> unuseable and sold it cheap. I couldn't think why something simple like a
> adapter ring wouldn't work and bought it.
> Unfortunately, he was right. It really doesn't work... it can't be turned
> far enough in the camera bayonet. There is about 10deg rotation missing,
> it just stops and can't turned further.
> I examined the lugs and saw that the ring (a 28/90 version) had some tool
> marks at the lug that moves the finder masks. Obviously, someone tried to
> convert this ring from 28/90 to 50/75 or 35/135 by removing material from
> this lug. There was some wear at the lugs, but nothing like the smoothly
> working bayonet of my 1964 Elmarit 90mm... that one looks bad, but works
> like a charm. The CV ring doesn't have any dents or obvious damages, only
> the lug for the finder has a filed front edge.
> When turning the lens, the bayonet lugs move under the slopes of the flat
> springs under the camera lugs. The lens is held against the bearing
> surface of the camera by these springs. Is it possible that the filed
> off lug doesn't glide correctly under the spring but catches it with its
> damaged edge?
> Unfortunately, it's impossible to see the movements of the various parts.
> Does anyone have an idea if its possible to repair this ring?
> Gr??e aus Hohenlohe,
>        Martin Jangowski
> | Martin Jangowski                         E-Mail:|
> |                        Netzwerke und Multimedia                     |
> | Voice: +49 7946/940790                         Fax: +49 7946/940791 |
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Replies: Reply from martin at (Martin Jangowski) ([Leica] Interesting problems with M39-Leica M adapter)
In reply to: Message from martin at (Martin Jangowski) ([Leica] Interesting problems with M39-Leica M adapter)