Copal press shutter service

I have a Copal Press-no.1 that would benefit from a cleaning of the blades, which have visible spots. 1/125 and 1/60 are slow, rest are ok.

There are four screws on the rear, passed the aperture cam. Removing those should allow removal of the diaphragm unit and reveal access to the blades?

If anybody has some documents or guidance it would be appreciated.

Well I jumped in. You gain access to the blades by removing the four silver screws and aperture housing. There are two springs resting on the housing, adjacent (right side from the back of shutter) to the preview lever, so it's better to pry open the housing from the opposite site. I didn't and the blades fell off. Those springs are for holding the preview lever open and for the sprung detent indexing the shutter speeds.

With the name plate at 6 o'clock, the first blade is placed on the post on the left. It should appear more or less perpendicular. Then superpose the blades counterclockwise, with the little spacers on blades 3-4-5. The the 6th blade goes onto the first. Carefully replace the housing by pushing on the springs at an angle then down. If you align it correctly with the screw holes it'll click in.

I also had to open the front and adjust the location of the preview lever spring (it would not lock open), and retension the indexing detent. In hindsight I should have removed those before removing the housing.

Will all that done, shutter speeds are the same: no improvement

Congratulations for getting it back together again! Apparently the problem is in the timing mechanism. As I recall, there are some Copal repair documents in the "Learn Camera Repair" site.

Thanks. The press shutters are a little different because of the self-cocking mechanism. I have a Copal Polaroid in no.0 size and the top speeds are almost identically slow. I suspect a full rebuild would be required. But there is some black grease on the levers and pivots and I wouldn't know what to replace it with.

There is a Polaroid MP3 copal repair manual on eBay but the shipping costs is a little steep (for Canada).

OAPOli said:

Thanks. The press shutters are a little different because of the self-cocking mechanism. I have a Copal Polaroid in no.0 size and the top speeds are almost identically slow. I suspect a full rebuild would be required. But there is some black grease on the levers and pivots and I wouldn't know what to replace it with.

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I've been using Super Lube that I got from Micro-Tools (AKA Fargo Industries). He sells lubricants specifically meant for camera repair.

Edit: It might be worth snooping around Learn Camera Repairs further. I found a detailed examination of the Ilex Universal in a section devoted to discussion of dual-escapement designs.

The black grease on the levers might be molybdenium grease. The most accessible source for moly grease is for auto work, a bit heavy for a shutter.

Two good sources for grease on Ebay-


The owner of the microscope grease store is very helpful. A message via Ebay and he could probably recommend some good products.

Often grease will both collect dirt and spread over time so what you see on opening up an old shutter can lead to excessive re-lubing. A very light grease in critical places will work 90% of the time. Or a light oil- the black could be oil and dirt.

You can polish the blades clean and then apply a film of dry moly and rub off as much as you can. If there is a central ring that all blades attach to, clean that and the pathway. Dry moly, maybe the lightest of grease and wiping a lot of it away, might work. Best to go light and add more lube precisely as needed than to over-lube.

Thanks guys!

Now that I think of it, my speed testing is not rigorous. I'm using a laser arduino module. When aiming in the center I get longer times vs aiming on the periphery of the opening, which are close to spec. It makes sense because the shutter takes time to opens and close. But since it acts like a diaphragm, when the shutter is half open you get only a quarter of the exposure. (That's why there are weird bokeh effects with high leaf shutter speeds). That transistion is negligible for 1/30 and longer. Actual exposure would be somewhere between the two.

I think I'll just leave it as it is, small overexposure is the worse that can happen.

Well apparently the nominal speed is determined at the shutter periphery. It's perfectly normal that the shutter would run slower on centre, and one should compensate up to one stop when using small f/numbers and fast speeds. Usually this affects 1/500 and 1/250 (opening and closing take ~1ms each according to Calumet), but it seems press shutters are a bit slower (4ms each way in this press no.1).