K-3 lubrication and adjustment

Eugene Zagidullin · May 18

I made a big mistake and forgot to mark all gear positions before disassembling. So now I'm struggling to figure out how to align the shutter and the claw properly. I suspect that in the stopped position the claw must be positioned in the exact centre of the slot. With the claw positioned like this the shutter blade can't be perfectly centred relative to the frame. I looked at some photos I was able to find and found the the blade on many of them is positioned slightly to the right with it's center pointing to the frame's edge. Can someone confirm my findings?

Also what kind of lubricant would you suggest for the governor axle bearings? At least a grease or an oil? All other bearings seem to be greased.

Simon Wyss · May 19

You have unidirectional pressure between gears. One tooth flank rolls over the other. That calls for the thinner lubricant the faster it goes. From the first gear on the spring barrel to the next you use grease. The fastest moving parts of claw and shutter will be oiled. What’s important with lubrication is that the oily parts can flow after the surfaces that rub.

Shafts in plain bearings are under directionally changing forces, therefore greased. They can vibrate, if dry. Oil alone runs away.

Correct alignment of the elements is self-explanatory. Film transport must take place while a shutter wing covers the aperture. On halt of the mechanism, spring giving energy, the aperture should be covered. Within limits you can adjust when the cycle begins. Try to set to aperture just shut so that the governor has the longest possible time to speed up on release.