Does Anybody Here Have Experience Working On Iris Shutters?

[galaybeing]

I'm an aspiring shutter overhaul tech but lacking enough experience. I've worked on a few now (self taught), but need someone to answer a few questions. I'm able to disassemble and clean, and get these shutters bask to a usable state, but don't seem to be able to get any kind of accuracy above 1/100. Frankly I think I'm dealing with old tired springs and have about concluded it's just not possible. Thank you.

 

[rick oleson]

A decent case can be made that it’s impossible to obtain accurate consistent speeds from a leaf shutter above 1/100, simply due to the opening/closing geometry of the shutter and the variable aperture iris. This might be of some interest by way of explanation:

 

[galaybeing]

I need to know what this spring does in a Synchro Compur 1 MX shutter. It is part 697 and I discovered it bent upwards at the lower end and no longer can be caught by the teeth of the control lever as it is rotated. (if that's what it is supposed to do).This is an important question, as I'm in a bit over my head. Thank you.

 

[monopix]

I'm an aspiring shutter overhaul tech but lacking enough experience. I've worked on a few now (self taught), but need someone to answer a few questions. I'm able to disassemble and clean, and get these shutters bask to a usable state, but don't seem to be able to get any kind of accuracy above 1/100. Frankly I think I'm dealing with old tired springs and have about concluded it's just not possible. Thank you.

How are you measuring the speeds? As Rick's comment shows measuring speeds is not straight forward. The effective speed depends on aperture as well as the actual speed. The method you use will effect the results you get.
That manual you have for the Compur has a table of speeds that should be measured through the centre of the shutter. At 1/500 the measured speed should be, nominally, 1/370. The speeds are deliberately set on the slow side to compensate for the low efficiency when using wide apertures and fast shutter speeds. Which is why you'll find compensation tables that indicate you should UNDER expose when using fast shutter speeds and small apertures, when the shutter efficiency is at its highest, to prevent over exposure.




From the Kodak Professional Photoguide. Text explains this is the suggested amount of UNDER exposure.