Sigh.
I own two semi-antique (or at least old) Carl Zeiss Jena Tessar 50mm/2.8 M42 lenses.
Yesterday, both decided that their apertures would not properly close.
I have to admit that the guy who lubricated their focusing screws a year ago just might have been overdoing the oiling a bit… (after all, it was I). But what’s the probability that they would both go bad exactly the same day?
I have to get that lens spanner that I yearn for…
Have fun!
Claes in Lund, Sweden
When the chaos is over, you’ll have to get them properly serviced!
Oh no. I want to be able to fix them myself!
W-e-l-l…
a) yes, but…
b) what a horrible price!!!
c) I’d very much prefer a source within the EU.
One of my earliest career aspirations was camera repair. I’ve ended up shunting all that tinkering obsession into software instead…
It amazes me what tools cost anymore. Good ones, that is… One would think that, with all the CNC and 3D printing capability, precision tools could be made very cheaply. But i think the economics are probably similar to that of cameras, in that the high-end volume is not that great, and it still takes substantial tooling to make tools…
Happy Spanning!!
Have you watched AvE videos on youtube? couple of them explain the gist - it’s the same cost and energy to produce good tool as it was years ago. However you can produce crappy tool for much cheaper than previously 
@Claes - what is the possibility that the lubrication you used has dried and become sticky? Maybe they just need to be cleaned?
Morning, @grsnovi,
Good idea, but no, I do not think so; not in this particular case.
The focusing helix still is smooth as silk.
Have fun!
Claes in Lund, Sweden