Krasnogorsk K3 Kooky Konundrum

Samuel Berger · September 24, 2017

So my immaculate, near pristine K3 arrived today. First thing I did was test the wind-up system and press the trigger. Well, whoever had it last had it set to 60fps.

I went on to read the manual, and wouldn't you know it, it specifically says in various places DO NOT RUN THE CAMERA AT HIGH SPEED WITHOUT FILM.

What catastrophic malfunction should I expect now that I unknowingly broke that often-repeated sacred rule?

At least I didn't feed it after midnight.

Gareth Blackstock · September 24, 2017

I would guess that if you run it at 18 or 12fps, it should tell you immediately if there's a problem?

Gareth

Samuel Berger · September 24, 2017

I would guess that if you run it at 18 or 12fps, it should tell you immediately if there's a problem?

Gareth

Unfortunately I don't know what problem it could cause, so I don't know what to look for.

Gareth Blackstock · September 24, 2017

Well I reckon if the spring motor runs at speeds you can discern, without fluctuating, I would hazard a guess that all is well. I think the only damage that could occur would maybe be to the spring? I'm sure some one with more knowledge would pipe up soon.

Apparently the cameras are pretty hardy, and when desperate they can be used as weapons, and still keep filming.

Apparently an early soviet requirement for war time purposes....

Edited September 24, 2017 by Gareth Blackstock

Robert Hart · September 30, 2017

If you shut the camera off before the spring power expired you may be in with a chance. At high speeds, any clockwork mechanism develops inertia which can over expend the spring, damage it or cause it to detach from fixtures. If it has not yet broken then it may well be okay but the spring may be fallable over the long term if end hooks or loops have become deformed, doubled-under and straightened with the rewind.

Edited September 30, 2017 by Robert Hart

Dom Jaeger · September 30, 2017

I was always under the impression that running a clockwork camera at top speed without film could potentially damage the pull-down claw rather than the spring. Running with film doesn't necessarily slow the spring down much, it will still be unwinding at a tremendous pace, and fighting the resistance of the gear chain, but I always imagined the film perfs provide a sort of guide for the claw movement and prevent it potentially deforming at very high revolutions The claws on these sorts of cameras are fairly flimsy strips of aluminium spinning on an offset pivot.

I could be wrong though!

Robert Hart · October 1, 2017

The claws are often tough steel-based material, hardened against wear. High time pieces will get a slot worn in them and begin to pull at film with a increasingly louder tick as they withdraw after each pulldown. Some designs are a little more inclined to do that than others.

Aluminium would not endure very long at all and has a finite fatigue life.

Running a film transport unladen at high speeds may increase stress as the claw downstroke will over-run without the film mass and gate friction to dampen it. The drive crank or cam may impact against the returning crank mechanism, a little like the destructive valve-bounce in automotive engines.

Samuel Berger · October 1, 2017

So far I haven't really ran into any issues but I've only shot 50ft of film in it. I should be finishing the current roll soon and then checking for any malfunctions. Good thing these cameras are almost dirt cheap.

I'm using a roll of Plus-X that's over a decade old, so I can test the camera for everything including light leaks. Fogging due to age won't bother me. Although now that I think about it, it might be smart to overexpose one stop since it's 12 year old film...

Dom Jaeger · October 2, 2017

The claws are often tough steel-based material, hardened against wear.

Aluminium would not endure very long at all and has a finite fatigue life.

In Arris and Aatons and Eclairs and such, for sure, but not in amateur cameras. The Bolex claw for example is anodised aluminium with a bronze bushing for the pivot, and it does wear over time. To adjust the claw travel arc as described in the service manual you use a tool to basically bend the claw to follow the groove in a jig that fits in the gate!

Out of interest, the pulldown claw in the spring-driven Bell and Howell Eyemos and Filmos is steel if memory serves, and the manuals have no warning about running the camera at high speeds without film.

Luigi Castellitto · October 4, 2017

I have a similar question.

I've had a K3 for many years, that I bought the same as the new one.

Some time ago the tripop with the camera had dropped to the ground, the camera lightly slammed.

I continued to shoot with it, I saw the films, but I did not find any problems. Apart, in films, the usual light leak, very rare the light spots, but I think this is a problem for all K3

What do you think?