PDA

View Full Version : Compound Shutter



MAubrey
3-May-2016, 13:24
I finally found a compound shutter that will fit my Symmar 360mm f/5.6 barrel lens. It's not in super great shape. According to the seller, the shutter sticks at 1", but works (with unknown accuracy) at all other speeds (but B & T don't work either). I'm considering buying it and getting it serviced, but I'm still nervous because I know from SK Grimes' discussion of them (http://www.skgrimes.com/library/used-obsolete-discontinued-shutters/compound) that often times these compounds are impossible to repair--either because someone dumbly dipped it in solvent thinking that would work or because they tried to force the shutter to cock for the B/T setting and broke the mechanism. It also might be that the seller things B/T don't work because they can't cock it and they're actually working just fine.

Presumably, the fact that the shutter actually does work on some speeds suggests that it could be serviced successfully?? Maybe? I just don't want to drop the money and end up with a crap product at the end of the day.

Any opinions or experience on this?

Luis-F-S
3-May-2016, 14:06
Why not call Adam Dau at SKG and get his take on it? At the end of the day, you pays your money and you takes your chances...........L

MAubrey
3-May-2016, 15:00
That's a good idea.

Thanks!

Bill_1856
3-May-2016, 19:03
Carol at Flotut's did a nice job on my old Compounds (which I love).

LabRat
4-May-2016, 06:17
If everything is moving smoothly, but maybe a little sluggish, it should be fine after a CLA... I think the issues that have been brought up about some old shutters are about if it were flood cleaned before, is that some iris and shutter blades were made of rubbers, plastics, paper, etc that would be damaged/warped/stuck together, and possibly further damaged if forced to operate afterwards...

Hint: Old Compounds/Compurs ran with very little lubrication, but depended on very smooth metal to metal sliding contact points... Some of the points/arms etc were aluminium that would slightly oxidize with a very slightly sticky finish, or old brass would build up oxidation/tarnish/corrosion (like in the air pistons)... A good tech would know how to clean and polish these points...

More often than not they can be returned to working if they haven't been messed with with, or just totally worn out...

Steve K

Jim Andrada
4-May-2016, 10:50
Carol at Flutot's did a good job on one of my old Compunds a few years back.

MAubrey
4-May-2016, 15:58
Hint: Old Compounds/Compurs ran with very little lubrication, but depended on very smooth metal to metal sliding contact points... Some of the points/arms etc were aluminium that would slightly oxidize with a very slightly sticky finish, or old brass would build up oxidation/tarnish/corrosion (like in the air pistons)... A good tech would know how to clean and polish these points...
That's a dangerous thing to tell me. I've reversed oxidation on aluminium and other metal parts before. Never in a shutter. But knowing that's the issue tempts me to disassemble it myself for cleaning. But I shouldn't. While I'm pretty good with mechanical things. I know something as intricate as a shutter is beyond the scope of my skills. It'd have to go to SKGrimes or Flutot's.

Still, this is precisely what I was wondering: if it's working at some speeds, it should still be repairable.

Jim Jones
4-May-2016, 18:21
A compound is a fairly simple shutter. If the shutter speeds are off, it may be no more than a build-up in the air cylinder. Probably the caps on each end can be removed. Introduce a little solvent into the cylinder with the shutter inverted to keep the solvent out of the other mechanism. Work the piston back and forth. Let all of the solvent completely evaporate before testing the shutter speeds.

pjd
7-May-2016, 08:56
Removing the piston from a Compound shutter for cleaning isn't difficult, with the top cover off you'll see two screws holding the piston in place - remove the two screws, and the piston assembly lifts off, allowing easy access to the end caps. You might need to cock the shutter to access one of the screws. Those pistons are supposed to run dry, I think Grimes are a bit suspicious of shutters that have been "worked on" this way and that. By tinkerers like me ;)

B&T not working sounds a bit more tricky though. Maybe a job for a pro. I have a compound that wasn't working properly on T setting, it turned out a spring had slipped out of place, it was an easy fix - but that shutter might be a different case. It rather depends how cheaply you can buy the shutter in the first place.

MAubrey
1-Sep-2016, 13:22
As a follow up, I bought the shutter.

It isn't super pretty, but's functional. I did a partial disassembly and now it's not sticking at all. The B&T settings still don't work. For some reason, the gear that's suppose to catch when you move to B or T isn't catching. I can see the problem internally and I can fix when its opened up, but after it releases it goes back to not catching again. I think I'll be able to survive that. I'm happy and I'd say I made the right decision. For $175 total, I've now got the lens, the barrel-aperture iris, and the Compound 4 shutter with the right aperture scale.