Repairing a 1970s rangefinder

It arrived in a shoebox with the lens cap wedged on backwards and a note saying "shutter sounds fine, focus is stuck". The note was half right. The shutter did fire, at one speed, which is not the same as working. The focus ring did not move at all.

These bodies are not rare and they are not precious, which is the nicest thing about working on them. You can make a mistake and the worst case is that a camera that was already broken stays broken.

Getting in

Remove the wind lever, the rewind knob, and the ring around the shutter release. Three screws under the leatherette at the front, two at the back, and the top plate lifts off. I use a strip of thin plastic to peel the covering instead of a blade, because the covering is old enough that a blade will cut it rather than lift it.

Inside it is mostly empty space, which is reassuring. One gear train on the wind side, the rangefinder assembly on top, and a lot of air.

The actual problem

Old lubricant turns into something between wax and glue. The helicoid that carries the lens had a thin film of it, thirty years of dust settled into it, and no willingness to rotate. The fix is not force. Force is how you bend a focus tab and turn a two-hour job into a two-week one.

Heat, then solvent, then patience — in that order. If it still will not move, go back to heat.

A hairdryer on low, aimed at the barrel for a few minutes, was enough to get the first millimetre of movement. Then a drop of naphtha into the seam, worked in gently, and after twenty minutes of small back-and-forth movements the ring came free. Once it moved, it needed to come apart anyway to be cleaned properly.

Cleaning and relubricating

The old grease comes off with naphtha and a lot of swabs; the threads then get a very light coating of a synthetic grease, far less than looks correct. The most common mistake in this repair is putting back too much. Excess grease migrates onto the aperture blades and then the aperture is stuck too, and that is a much worse afternoon.

Reassembly is the reverse, with one adjustment: the rangefinder has to be re-collimated after the helicoid goes back, because nothing about this process is precise enough to preserve the original setting. Infinity first, at a distant roof or a streetlight a long way off, then the near end against a measured distance.

Verdict

Total cost: a few hours, one missing screw replaced from a jar of spares, and a roll of film to confirm the shutter was now doing more than one thing. It is not a valuable camera now. It is, however, a working one, which is more than it was on Friday.

The note in the shoebox was wrong about the shutter and right about the patient part. Most of these jobs are patient part.