Kowa Six 110mm lens

[campy51]

Picked up a Kowa Six with a 110mm macro lens and extension tubes. Everything in very nice condition except the lens focus is stiff. You can access the some of the focusing helical without removing everything so has anyone had any success cleaning and lubing without total disassembly?
How does it perform as a general use lens?

 

[Kino]

I have had limited success reviving stiff lenses on rangefinders without removing them, but there are potential issues that arise from this practice.

More "modernish" lenses with yet fluid, but stiff lubrication can often be revived by injecting tiny amounts of new helicoid grease into the exposed gears and working it repeatedly. The action will smooth-out eventually but it may revert to binding again after a short period.

If the lens has been exposed to dust, and you do this, you make a fine grinding powder that will eventually wear out the helicoid.

If you put too much new grease into the helicoid, it will push out the other side and drop into the shutter and/or aperture assembly.

With really stiff lenses, you run the risk of stripping out the tiny set screws that anchor the focusing scale to the helicoid, throwing your focus chart off or making focusing in general impossible without disassembly and repair.

If you have any camera with the "green snot" type of lube used in early German and Japanese rangefinders, this typically will not work, as the grease does not typically respond to this treatment. In my experience, this grease tends to petrify and the only solution is total disassembly and physically scraping/chiseling off the stuff.

It is a gamble, especially with a lens with an integral shutter, but that is up to your judgement.

 

[OAPOli]

If you remove the rear plate and cocking ring, you'll get access to the helicoid keys. You can remove those and pull out the lens block with male helicoid. Then you can clean and regrease the main helicoids. Remember to mark the exit point.

To clean the focusing grip thread I *think* you need to remove all the shutter control rings. If the lens got bumped the focusing grip can become askew. You can reset it (and the infinity position) via the three set screws.