Leitz 40mm f/2 Repair and Focus Tap

Erik Gunst Lund

Kind regards Erik
Local time
3:17 PM
Joined
Feb 15, 2009
Messages
28
Location
Copenhagen
My Trusty little Leitz 40mm f/2 was suffering from aging grease, Canada Balsam and the internal black paint had begun to become detached also so a repair was needed I also wanted to add a modern focus tap.
Since the lens is so cheap I decided to try it out myself.
I have a lot of knowledge about AF and MF Nikkor, Cannon Olympus and Voigtlanders SLR and Leica mount lenses, most parts of the design and build is same same 🙂 but this tiny Leica has some differences as to how it's put together, first I was very disappointed to find that the front threads part series 5.5 threads is glued to the aperture housing, next I found that the rings that 'normally' have two holes or ridges for lens spanners for tightening the old Leitz lens had one or even none, so had to be taken apart with friction, a rubber tube of the right thickness must be used to reach into some parts of the lens to get it apart, I modified these rings, drilling two holes makes the hole deal a lot easier.
Got it all dismantled and sorted out, the two elements with the Canada Balsam issue got a 'cooking' treatment in boiling water to separate the two halves.
A drop of Araldite Krystal and the two are inseparable, a coat of mat black paint to finish the job off.
Putting everything back together without leaving dust or prints is the worst part...
The old gease was cleaned off and the many threaded focus threads lubed with new grease and put back together as marked by disassembly.
The new focus tap needed a slight trim to clear the mounting ring and two extra location holes to keep it in alignment a single screw holds it in place.
Everything fits within very tight tolerances; position of glass elements, focus threads so it was a joy to work on it.

8057350491_49f24340ba_b.jpg

All the parts, note extra holes, the two glass element front center

8057350337_82e5199964_b.jpg


Extra holes for focus tap in focus mount.

8057350368_18a6ab2d0c_b.jpg


Focusmount with focus tap.

24 hours wait for the Epoxy to cure and testing today went very well, focus at infinity and all the way to 0.7m is spot on.
Lens is now in good service condition and much closer to my heart
smile.gif
 
Thanks!

Re-cementing the two elements is definitely not easy with Epoxy since it sets so fast, a drop of glue, without air bobbles, is placed at the center then you press the two elements together you must keep them centered, in total you have 5 minutes before the glue sets from you start mixing the two components.
 
Yes it does. I found that the most common Glue at factories are now an UV cured Epoxy, simply expose the glued elements, when centered, to UV and it hardens, very neat indeed.
 
Thank you for your answer to my question, you state that epoxy cement is used now for optical assembly. I believe that the UV curing cements are in fact acrylic, that is what I have found in my experience.

Best,

normclarke.
 
Back
Top Bottom