1936 Plaubel Roll-Op Service

I set aside a day to get this Plaubel Roll-Op serviced. I'd never worked on a shutter this old before (1936 Compur Rapid) and of course, every manufacturer of the Compur Rapid did it a bit differently, different components and gear trains and so forth. Chris Sherlocks video on servicing compur-rapids was invaluable. Anyway, here's some photos from the experience.

Setting up

After figuring out how to remove the shutter from the body.

Getting the nameplate and the shutter speed cam out of the way

A look at some very oily shutter blades

10 even oilier aperture blades, it only took 5 attempts at setting the blades to get it right. Pain in the dick.

After cleaning and reassembly

State of the rear element before a clean with ammonia and peroxide

After cleaning, there's a little etching but you gotta get it in just the right light to see it. I don't see it effecting the final image

I also needed to replace a mirror in the rangefinder section, this is the old mirror

And this is the new mirror in place, had to cut it myself and it was the first time I'd ever done any glass cutting.

All done!

Now, how does it work?

What you're looking at here is the shutter with the cam plate on it. The shutter is currently in T mode (this opens the shutter on one release, and closes it on the next, T for Time), you rotate the plate to select speeds so in this case, as we rotate counter-clockwise we're adjusting the speed from 1 second to 1/400th of a second.

What sets the speed is the blue component. This is the retard gear train follower, as that follower lowers, the shutter speed gets longer, it's currently in a fully disengaged position for T and B modes, it's all the way up as the shutter is not cocked.

The red component is what engages that gear train, it'll ride that steep slope upwards and allow the gear train follower to drop into that valley, selecting the shutter speed

The orange component is the cocking lever, there's a big spring attached to it that supplies the energy to fire the mechanism, this spring pulls a ratchet against the retard gear train to, you guessed it, retard the motion of that gear train and slow it down. The gear train has to travel through it's entire range of motion before the shutter will close again. By limiting the range of motion you can set shutter speeds.

The purple component is the high speed spring. Getting speeds up to 1/400th of a second is difficult, their solution, add a big ol spring that only engages for that speed, adding energy to the system to snap the shutter through as quickly as possible.

The green is the shutter release lever. You can see the lever it's engaging. When you move that lever out of the way the cocking lever can release its energy. Through its range of motion it will open the shutter blades, keep them open until the time elapses, then snap them shut.

The only other major component in that mechanism is a self-timer. It'll delay firing for 10 seconds so you can set up a shot then run out and get in the photo. It's hidden under the plate. All the other components are springs and catches to makes sure things stay in the right place, get caught at the right time and release only when intended. Under all of this is the aperture which is some interleaved blades that let you choose your depth of field and how much light you'll let through.