Sticky Summar 50mm f2 aperture dial
I'm the lucky new owner of a 1936 Leica IIIa, and the lens is a little worse for wear. The aperture dial works fine , but it sticks and jams, and it would probably live longer if it was lubricated somehow.
But there's the general warning about cameras and grease and oil, and how some things really shouldn't be lubricated that way.
So, how would I spruce up my lens? I'm probably technically able enough to do what is needed, but I'm going to take it slowly. I'm not going to dive in and experiment.
if you think you're lucky...
to score that nice camera (and I concur), I'd have it sent out for a CLA.
IF you've done lots of camera repair yourself already, I'd consider getting a service manual for the lens before diving in.
I have a Summar that came in with a sticky aperature and tough to move focus ring, as well. I spent an evening watching television while cycling both lens functions, and they freed up nicely enough to use without difficulty.
I was hesitant to send mine in for a CLA as the glass had bloomed to the point that it looked coated and didn't want that removed. For all the disparaging comment about Summars, I really like the lens and it's distinct look.
The nice thing about the RF lenses is they have No stop down linkage.
The front group of the Summar should drop out the front once the retaining ring is removed. Check around the perimeter for set screws. The aperture assembly May be removed the same way, again, check for set screws.
I'd be careful since you say the aperture ring jams. It could be more than old grease something like a bent or torn blade. For what it's worth I use penetrating oil on a Q-tip to clean out old lube.