Alpacaman
keen bean
My Zorki 4k seems to have fast slow speeds - 1 second is always more seems to be 0.6-0.7 seconds. While it may not be a big deal, it is really bugging me, and I would like to fix it. I have tried moving the pallet (I think that is what it is called) closer to the star shaped wheel, which seems to be the only way of adjusting the speed of the escapement, but when I move it closer it simply jams. I currently have it as close as I can get it without jamming it, but it is still running fast. Is there any other way to slow it down?
wolves3012
Veteran
You could take some tension off the spring that powers it, that'll slow it down. If you read the sticky thread on CLA-ing the 4K it'll show you how to get at the mechanism. The spring is held at the top end by sitting in a cross-slot, it can be pulled out from there once it's unwound.
You'll need to be pretty careful and it might take a few attempts to make it run correctly. DON'T be tempted to pull the spring off the post when it's tensioned - it'll rip your fingers or fly off and you'll have no idea how much tension was on it to start with. Let it unwind in a controlled way (like keeping your fingers on the large gear), making a very careful note of how far it turns, then lift the spring, move the mechanism (say) one turn, then replace the spring and wind it up again - remember to subtract or add the turn to the mechanism to get back to your start point, that's the crucial bit!
The position of the pallet has no effect on the speed, only the spring tension does.
You'll need to be pretty careful and it might take a few attempts to make it run correctly. DON'T be tempted to pull the spring off the post when it's tensioned - it'll rip your fingers or fly off and you'll have no idea how much tension was on it to start with. Let it unwind in a controlled way (like keeping your fingers on the large gear), making a very careful note of how far it turns, then lift the spring, move the mechanism (say) one turn, then replace the spring and wind it up again - remember to subtract or add the turn to the mechanism to get back to your start point, that's the crucial bit!
The position of the pallet has no effect on the speed, only the spring tension does.
sevo
Fokutorendaburando
A half stop towards the extremes seems pretty well-behaved for a soviet camera, and might be hard to improve short of machining higher precision parts for it. Be cautious fiddling with the tension - this might screw up the more important shorter times.
Sevo
Alpacaman
keen bean
Okay, thanks for the advice. I will have a go at adjusting it next time I have the Zorki's top off.
wolves3012
Veteran
Sorry but I'll have to disagree with the first part. I'm confident that all of my FSUs with slow speeds are within 10% of the correct speed. I do agree that some care is needed to ensure that the faster "slow" speeds aren't messed up. I have made the tension adjustment on a couple of mine though and it does work, just needs care and patience.