My Yashica D repair - call it good enough, or keep going?

PFGS · Oct 19, 2020

Last Friday I finally buttoned up the Yashica D I'd been working on over the last few weeks; I'm still a beginner at repairs. When I started, the viewfinder and mirror were filthy and the shutter was hanging on all speeds. When I was done, I shot a test roll at all speeds, and printed a contact sheet from it. Here's what I've got: viewfinder is clean and clear; focus, transport and frame spacing, and light-tightness are all perfect, shutter fires on all speeds and self-timer works (I never use it, but nice to not have it lurking as a jam waiting to happen), and the lenses are free of haze, fungus, significant dust, etc.

The remaining issue is that the speeds are still off, but I'm temped to leave them that way. Equivalent exposures from 1/500, 1/250, 1/125, 1/60, 1/30, and 1/15 (the hand-held speeds) are all dead-on the same, but they are all exactly one stop slow. I'm seriously tempted to leave it as-is and live without a true 1/500, given how the error is predictable and easy to adjust for, and given that this is my backup to a perfect, Mark Hama-serviced second Yashica D.

So what do you think? Should I dig back in, or leave well enough alone? I'm inclined to the latter, but wanted to make sure I wasn't missing something obvious, like maybe a misaligned speed cam or something.

shutterfinger · Oct 19, 2020

If you just flushed the shutter with solvent then I would disassemble it, clean all the parts then lightly lube them as you reassemble the shutter.
Its common for some speeds to come up 1 stop slow but 1/100 - 1/125 and slower usually come back correct.
The slow speed timing assembly may be adjustable.

PFGS · Oct 19, 2020

shutterfinger said:
If you just flushed the shutter with solvent then I would disassemble it, clean all the parts then lightly lube them as you reassemble the shutter.
Its common for some speeds to come up 1 stop slow but 1/100 - 1/125 and slower usually come back correct.
The slow speed timing assembly may be adjustable.

I did more than just a flush, a partial disassembly, but could not do a full disassembly because two of the four screws that would allow me to take it down to the individual shutter blades are in poor shape. I was able to remove the slow speed and self timer assemblies and clean them well, and adjusted the slow speed pallet gap wider (faster) very slightly and am getting a just slightly slow 1 second time. 1/2, 1/4, and 1/8 run progressively slower from there, and then 1/15 to 1/500 run 1 full stop slow but as my exposures show, do so in a very evenly spaced and predicable manner.

I did not add any lubrication as I found a lot of mixed advice on that.

BrianShaw · Oct 19, 2020

Dig back into it. Judicious lubrication this time. Watch some of the shutter overhaul videos of Chris Sherlock. He has a new series on a Rolleicord Vb that might be very useful to you. In his shutter reassembly programs he always addresses timing adjustments.

shutterfinger · Oct 19, 2020

I've got a Prontor SVS open right now and I don't expect it to ever work again. Prontor stated not to use any oil in their shutters. They would have lasted longer if they had. I have disassembled the speed timer on Compur and Prontor shutters and lubed them on reassembly. Wear is the the most determining factor as to in tolerance operation with weak springs the second. Weak springs can be improved by heat treating them as described in the latter steps of http://www.deansphotographica.com/machining/projects/springs/springs.html . I always lube shutters sparingly regardless of manufacturers run dry instructions. Oil makes shafts turn smoother and quieter. New shafts are polished smooth, used ones are not. I use TriFlow https://www.amazon.com/Tri-Flow-Squeeze-Bottle-Lubricant-Teflon/dp/B00GC54OC2/ref=sr_1_2?crid=3NH6D4DTVAKLY&dchild=1&keywords=triflow+superior+lubricant&qid=1603143027&sprefix=triflow,aps,412&sr=8-2 , available at hardware stores and bike shops. I use a trace of oil, you can barely detect a light sheen. For bushings flushing them out with the shaft removed gets them cleaner, I stick a round tooth pick in the oil fr 5 to 10 seconds then insert the oiled end of the toothpick into the bushing and turn it around a few turns then reassemble the mechanism.
Blade controllers with blades should move freely with the weight of a small feather on their operating post, all springs released.

Some shutters are worn enough that they will not return to speeds being in tolerance.
https://www.flutotscamerarepair.com/Shutterspeed.htm

PFGS · Oct 19, 2020

shutterfinger said:
I've got a Prontor SVS open right now and I don't expect it to ever work again. Prontor stated not to use any oil in their shutters. They would have lasted longer if they had. I have disassembled the speed timer on Compur and Prontor shutters and lubed them on reassembly. Wear is the the most determining factor as to in tolerance operation with weak springs the second. Weak springs can be improved by heat treating them as described in the latter steps of http://www.deansphotographica.com/machining/projects/springs/springs.html . I always lube shutters sparingly regardless of manufacturers run dry instructions. Oil makes shafts turn smoother and quieter. New shafts are polished smooth, used ones are not. I use TriFlow https://www.amazon.com/Tri-Flow-Squeeze-Bottle-Lubricant-Teflon/dp/B00GC54OC2/ref=sr_1_2?crid=3NH6D4DTVAKLY&dchild=1&keywords=triflow+superior+lubricant&qid=1603143027&sprefix=triflow,aps,412&sr=8-2 , available at hardware stores and bike shops. I use a trace of oil, you can barely detect a light sheen. For bushings flushing them out with the shaft removed gets them cleaner, I stick a round tooth pick in the oil fr 5 to 10 seconds then insert the oiled end of the toothpick into the bushing and turn it around a few turns then reassemble the mechanism.
Blade controllers with blades should move freely with the weight of a small feather on their operating post, all springs released.

Some shutters are worn enough that they will not return to speeds being in tolerance.
https://www.flutotscamerarepair.com/Shutterspeed.htm

All right, TriFlow is in the cart. Any recommendation for a penetrating oil or "liquid wrench" product that might help with those two stubborn screws?

shutterfinger · Oct 19, 2020

Acetone aka nail polish remover. Not all nail polish removers are acetone based. Apply to a cotton swab then touch to the screw saturating it. Allow the acetone to soak in for several minutes, repeat as needed. Apply to the thread ends if they're accessible.

Donald Qualls · Oct 20, 2020

Not sure if this is appropriate for camera mechanics, but if you're using acetone anyway -- gun folks swear by a mix of acetone and automatic transmission fluid (not sure of proportion) -- acetone lets it penetrate, then the ATF coats and lubricates. BTW, you can buy straight acetone as a solvent at most hardware stores, in the paint section. Costs a lot less per volume than nail polish remover, and doesn't contain other junk (or turn out to be acetone free), but a pint is the smallest can they sell.

PFGS · Oct 20, 2020

Donald Qualls said:
BTW, you can buy straight acetone as a solvent at most hardware stores, in the paint section.

Yep - I always have lots of cans from that section, acetone, alcohol, naptha... we are always tinkering on something here.

Patrick Robert James · Oct 20, 2020

Getting the screws out would depend on what the screw is made of and what the socket is made of. It might be corroded in there. Using a soldering iron is another approach if it is. I usually use PB Blaster on regular "stuck" screws and bolts. That is another option. The Acetone/Transmission fluid is mixed 50/50 if you go that route. Gotta leave it soak in for a while either way you go. You might need a penetrant and heat.

You say you flushed it but unless you used an ultrasonic cleaner it will still be dirty in places. You might try that.

BUT If all speeds are slow, it is possible someone left it cocked for years and the spring has lost it's oomph. Without addressing that it will never be back in spec no matter how clean it is.

I'd leave it alone if it is predictable. Like they say, perfection is the enemy of good.

PFGS · Oct 20, 2020

Patrick Robert James said:
I'd leave it alone if it is predictable. Like they say, perfection is the enemy of good.

Right? There are much worse ways the speeds could be off, than this entirely workaround-able correct-minus-one situation. But at the same time, since this is sort of my beater, it's tempting to just try for the sake of repair practice. Of course, it's not such a beater that I'd be happy if I screw up and trash it.

shutterfinger · Oct 20, 2020

Thread locker used in cameras is dissolved with Acetone.

Tel · Oct 21, 2020

Have you tried heating the stuck screws? I use a soldering iron (clean tip--no solder) for about 20-30 seconds on them before I try to unscrew them, and it usually works. Obviously, being careful of flammable solvents etc.

PFGS · Oct 21, 2020

TriFlow arrived today, so for some practice both with using it, and on shutters in general, I set the Yashica aside and tackled the "Ilex Precise" shutter on an original Argus A I've had sitting around. Took it right down to the bones, cleaned everything, buttoned it back up with a bit of TriFlow on the pivots, and it seems really happy. Should get back to the Yashica this weekend.

My Yashica D repair - call it good enough, or keep going?

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