If you are curious, I purchased the Turner-Reich Convertible 8.5/14/20 inch lens from a board member as a period correct lens for my Gunlach Korona 5x7 view camera. The shutter was advertised as working but inconsistent at lower speeds.
I got the shutter working reliably now after some cleaning and experimentation. It might have not even needed the cleaning, but I'm sure it didn't hurt it!
I found that the shutter speed dial might have been reassembled incorrectly sometime in the past and that the follow lever that rode on the little brass cam under the dial would pop-off track and then back on in the lower speed section. The "Mystery Washer" fell out of the stack of dial parts as I removed it. I was trying to be extra careful, but even then, I was unsure of exactly where it went in relation to the brass pointer, the "Y" bracket and the cam.
I disassembled and reassembled the speed dial about 7 times, finally figuring out the proper sequence of spacers and where they went. The secret to this was looking at the assembled shutter speed selector dial from the side to see when the cam follower would be engaged and not jump off the cam face or grind against the speed indicator wheel. Sorry, no photo of that...
I also had to slightly bend the cam follower lever upwards to offset years of wear. Now, all speeds appear to be roughly correct.
NOTE: This is a self-cocking shutter; the shutter is cocked and fired by pressing the shutter release or using a cable release.
One interesting note should you have a similar shutter in the future; I discovered why the speeds below 1/25th are inconsistent when rapidly fired. The escapement that controls the lower speeds is a gear train that must have time to "load" before you press the release all the way down. (See green arrow above) This is a direct drive-coupled escapement and it must wind through the range of motion each time you press the shutter.
In other words, as you press the shutter release, a lever pulls back and the escapement clockwork begins to wind back to its starting point. The longer the exposure, the longer it takes those gears to wind-back and fully charge. In order for me to get consistent speeds in this range, I have to depress the shutter release about half way down and listen for the gear train to stop buzzing before I press it the rest of the way. When I do that, the speed is consistently accurate according to the dial (more or less).
I speculate that we have been conditioned to expect instant or near-instant repeatability with our late 20th century mechanical camera shutters. In retrospect, it makes sense that a large format shooter would be slowly pressing the shutter release anyway, so the shutter has probably always relied on a slow shutter release. Go figure!
So if you have one like this, try pressing the shutter down halfway and wait a second, then fully press it down. You might not even have to clean it; just be patient!
I got the shutter working reliably now after some cleaning and experimentation. It might have not even needed the cleaning, but I'm sure it didn't hurt it!
I found that the shutter speed dial might have been reassembled incorrectly sometime in the past and that the follow lever that rode on the little brass cam under the dial would pop-off track and then back on in the lower speed section. The "Mystery Washer" fell out of the stack of dial parts as I removed it. I was trying to be extra careful, but even then, I was unsure of exactly where it went in relation to the brass pointer, the "Y" bracket and the cam.
I disassembled and reassembled the speed dial about 7 times, finally figuring out the proper sequence of spacers and where they went. The secret to this was looking at the assembled shutter speed selector dial from the side to see when the cam follower would be engaged and not jump off the cam face or grind against the speed indicator wheel. Sorry, no photo of that...
I also had to slightly bend the cam follower lever upwards to offset years of wear. Now, all speeds appear to be roughly correct.
NOTE: This is a self-cocking shutter; the shutter is cocked and fired by pressing the shutter release or using a cable release.
One interesting note should you have a similar shutter in the future; I discovered why the speeds below 1/25th are inconsistent when rapidly fired. The escapement that controls the lower speeds is a gear train that must have time to "load" before you press the release all the way down. (See green arrow above) This is a direct drive-coupled escapement and it must wind through the range of motion each time you press the shutter.
In other words, as you press the shutter release, a lever pulls back and the escapement clockwork begins to wind back to its starting point. The longer the exposure, the longer it takes those gears to wind-back and fully charge. In order for me to get consistent speeds in this range, I have to depress the shutter release about half way down and listen for the gear train to stop buzzing before I press it the rest of the way. When I do that, the speed is consistently accurate according to the dial (more or less).
I speculate that we have been conditioned to expect instant or near-instant repeatability with our late 20th century mechanical camera shutters. In retrospect, it makes sense that a large format shooter would be slowly pressing the shutter release anyway, so the shutter has probably always relied on a slow shutter release. Go figure!
So if you have one like this, try pressing the shutter down halfway and wait a second, then fully press it down. You might not even have to clean it; just be patient!
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