Disassembly - Leica Summilux-M 35mm F1.4 ASPH FLE 11663 lens

 This article is dedicated to focusing frame disassembly of quite interesting lens - Leica Summilux-M  35mm F1.4 ASPH FLE 11663.

I'd count this material as just an additional set of steps to already excellent article written by Gigantopik - Lens Repair / CLA Leica Summilux-M 35mm f/1.4 ASPH. Lots of pictures in that article are self explanatory and help a lot to understand lens optical and mechanical design.

First step is to use cylinder with adhesive edges to unscrew lens front nameplate in CCW direction. It will expose access to three silver bolts. They need to be accurately loosened and unscrewed. Be extra careful while using screwdriver close to glass surface, it may be good idea to protect glass with layer of soft leather.

Pull out hood mount ring. It has engraved dot which should be aligned to position where lens hood has elevated edge stopping mount-on rotation.

Then unscrew another set of three bolts and remove ring with aperture position indicating dot.

Next step is to remove brass compression ring holding aperture ring.

Take out aperture ring slowly, and find the small metal ball. It should be put back to aperture ring spring loaded socket shown in bottom area during assembly.

Unscrew another set of three bolts and disconnect optical core from focusing frame.

I think this is most interesting mechanical area of lens design - large brass ring around optical core is a FLE helicoid. It is moving three white plastic cylinders inside slightly angled sockets in cylinder walls. That white cylinders are holding FLE optical group. RF couple cylinder is rotating by brass transmission visible in focusing frame. That brass ring has socket for FLE brass helicoid visible as dark rectangle at 1st hour.

There is also set of thin calibrating ring shims between optical core and focusing frame.

Optical core frame also has two sets of hex headed black bolts on outer walls for precise optical alignment - do not turn them, otherwise IQ may significantly degrade.

Next step of disassembly is unscrewing 6 bolts on mount ring and disconnecting it.

Then gently pull out black brass frame holding RF couple cylinder and focus helicoid guiders. Memorize radial location of protruding pins to fit back during assembly.

Now it is possible to unscrew focusing ring. The thread is very thin and it takes 13 full turns of focus ring to unscrew it.

Focus helicoid inner ring need to be unscrewed next. Then it is posdible to unscrew three bolts and disconnect focus ring shell.

I'm assembling lens back together at this point after minor cleaning of dust and tiny sand particles. Grease is still in excellent shape and provides very smooth focusing.

Leica 35mm F1.4 Summilux-M ASPH. FLE lens is built with many precisely machined brass parts combined with lighter metal to reduce overall weight. It's not a surprise to see large number of precision calibration solutions for mechanics and optics made in Germany following highest quality standards.