Unicum shutter issues

[altb44]

I've looked on the forums for anything on cleaning a Unicum shutter, but didn't find much. Google didn't have much at all either, so I'm posting this.

I know these shutters are not very reliable with speeds, and apparently are not very good, but this one has been fine for paper negatives...up to now. It has a lever as well as a pneumatic bulb piston. I've been using the lever, and it's been working fine, then it started sticking, and now it won't go off the settings like before, though the shutter opens fine, with no lag. I have to nudge the brass dial to make the shutter close. I cleaned the piston last night, and all of a sudden everything worked well. All speeds were good. Perfect! Thought I'd fixed it.
Then today it's back to sticking.
Do I have to clean it more than once?

[Steven Tribe]

There are some useful previous threads with illustration - best perhaps here

http://www.largeformatphotography.in...Unicum-shutter

To be honest, they were not much help to me as my "plastic" iris blades are terminal!

I think that finding out what replacements are available for the various Sizes of Unikum shutters is the way to go.

[Pfsor]

. I've been using the lever, and it's been working fine, then it started sticking, and now it won't go off the settings like before, though the shutter opens fine, with no lag. I have to nudge the brass dial to make the shutter close. I cleaned the piston last night, and all of a sudden everything worked well. All speeds were good. Perfect! Thought I'd fixed it.
Then today it's back to sticking.
Do I have to clean it more than once?

Why would you clean the piston? Its function is just timing, not opening or closing the shutter. Clean the closing mechanism instead.
By the way, when Unicum gets its capricious mood it's time to see how miserable the construction is and find you a new friend.

[altb44]

Thanks both. I must have missed those posts, Steve.
I cleaned the piston because it was the most non invasive thing I could do and it looked gummy. It seemed to help...for a bit.
I should have also mentioned that I cleaned the mechanism around the lever and behind and underneath the shutter setting dial. The blades look fine, and since I've been told they are not metal, I'm avoiding opening the lens and cleaning them.
I'll take another stab at cleaning the shutting mechanism. Maybe I missed something. And yes, when it comes to the point that my Packard roller shutter is more reliable than this one...it's time to look for something a bit newer.

[altb44]

so...just wondering...if this shutter is toast what is a really good one for a 5 x 7? I'll look on the forums but would appreciate your advice. I like using antique lenses, and old processes but I'd love a shutter that behaved itself.
meanwhile, I'm just using lens caps.

[altb44]

Found the problem. A wire has broken leading from the speed setting mechanism to the lever and tube. Explains why the slow speeds wouldn't finish. The thread you referred me to helped, but here I am wondering what to do with a shutter that has a broken wire. i note from the other thread that he referred to a spring that had come loose. Same issue? If so...how do you replace it?

[Steven Tribe]

Photo please!

We might be able to help if we can see the part.

[altb44]

I knew I forgot something...a photo!

and a side view. It was tricky to get a photo of the broken wire

When I pull on this wire the shutter cocking mechanism works. When I let it go, it just flips back up. I think it's wound around inside but I'm hesitant to take this apart any further until I sort of know what I'm doing

[goamules]

You are asking about repairs on shutters that haven't been made in 100 years. Several generations have been born, grown old, and died since these were new. 99% of the camera repair shops have closed. These were never very great shutters anyway, and were replaced by 3 or 4 newer generations. Basically, you're going to have to experiment and figure out what to do yourself, unless someone suddenly chimes in that has worked on these.

I'd replace it with an Optimo or Betax if you want an antique one that often works. Or just buy another, working Unicum and compare.

[altb44]

I was only responding to Steven's request for photos. I assume he wishes to help.