After completing the service, cleaning, repair, adjustment on the 1936 Leica IIIa, I shot a test roll to see if everything was working as it should. There are a lot of things that can be wrong on an 80 year old camera. A test roll can show if the film is advancing correctly, getting the proper space between images on the negative, shutter speeds are correct, the rangefinder and lens are in good sync so the images come out good and clear. etc…
The first test roll showed that the shutter was at the right speed but on the faster speeds, it was not adjusted correctly. The second or “closing” curtain was catching up with the first curtain part way across the film area.
On this type of camera, there are two curtains that act as the shutter. First the opening curtain starts it’s travel then, depending on the shutter speed you choose, the closing curtain starts it’s travel. On this model, at 1/20 of a second the opening curtain has exposed the entire film area before the closing curtain starts it’s travel. At 1/500, it only gets about 1/8th of an inch before the closing curtain starts it’s travel. They travel together at 1/8″ across the entire film area. No matter what speed you set it, the curtains physically travel at the same speed, (about 1/20th sec.) it’s the size of the opening that determines the shutter speed. At 1/1000 shutter speed, the opening is about 1/16th of an inch, 1/200 about 3/16ths and so on.
So you can see, the curtains have to be adjusted so they travel at the same speed. After the first test roll, I had to take the camera apart again so I could see the shutter at work. (this camera and many others like it doesn’t have the back open to put in the film, you load it from the bottom so you can’t see the shutter working unless you take the outer shell off) I was able to tension the curtains so that the closing curtain wasn’t catching up with the opening curtain.
It’s very rewarding to take an instrument almost 80 years old and repair it and know it’s good for at least another 10-20 years before it will need to be cleaned and adjusted again.
Giving my 1936 Leica IIIa a CLA. It basically works fine, the shutter fires on all speeds but the slow speeds are sluggish. The curtains have previously been changed, maybe even twice in it’s 78 year history and look good. Overall there is brassing on the top and bottom plates but from normal heavy usage telling me it was well loved. From what I can see, the inside looks clean-ish, no major rust or anything like that.
Above, showing the external condition, dirt and a reddish oxidation to the Vulcanite (red circle) and dirty internal glass.
After getting the shell off, that’s a good time to observe the shutter action. Look through it against a florescent light. When I did mine I discovered the 1/500 speed had just a blip of light and the 1/1000 speed showed no light at all so now it’s a CLA and repair as well.
Lets remove the top plate to see the Timing Mechanism and RF glass. (on the III and IIIa, only the smaller plate over the RF comes off, on the later IIIc, IIIf and IIIg, the entire chrome top plate comes off.
While I was cleaning the old grease I noticed a stop-post on the second shutter release arm was leaning. I poked it and it wiggled. I tightened it and all speeds work now!
I cleaned old grease and re-greased the Timing Mechanism, winding knob, rewind knob shaft and Diopter adjust. I cleaned the gears at the bottom of the shutter drum.
12/23/14: cleaned the Vulcanite. a 3 step process and it looks great now. Reassembled the camera shell and slow speed dial.
Lets put it back together. The film pressure plate rides in it’s own groove milled into the back of the body shell. The two leaf springs have their own slots as well.
Now put the lens ring and slow speed dials back on. If you had shims under your lens ring, remember where and how they went.
This camera was fun to work on. It may seem intimidating but is actually easier to work on than the later Japanese rangefinders where you, a lot of times, must remove the leatherette to get to the lens plate to get to the shutter to get to the …blah blah.