Dial set Compur issue

[BarryS]

I recently bought a Schneider Xenar Typ D f/3.5 in an old dial set Compur shutter. The shutter seems to work except for one problem--the cocking lever is missing because it sheared off the screw heads that attach it to the cam that rotates and cocks the shutter. I have another broken Compur shutter with the lever still attached to the cam and would like to swap the cams so I have a fully functioning shutter. The cams appear to be the same part, but I'm wondering if they're likely to be interchangeable and if anyone has experience removing the cam and can tell me about the amount of disassembly required. Thanks.

[BrianShaw]

I don't exactly know. But this might give you some clue as to difficulty of opening. Hopefully reassembly is as easy as I imagine opening an disassembling will be.

http://www.davidrichert.com/dial_set_compur.htm

[BarryS]

Thanks Brian--that's very helpful as far as opening up the shutter. I guess I'll try opening up the trashed shutter and see if I can remove and replace the cam without the whole thing flying apart.

[BrianShaw]

I've never had a shutter "fly apart" but I've certainly had springs do that. Watch very carefully for spring placement before you start taking stuff out. I imagine that the cocking lever is directly attached to the strongest spring in the shutter. Knowing htat even tiny springs can go a fair distance and get lost... I imagine that bigger springs can go farther!

[BarryS]

My definition of "flying apart" goes down to a single piece flying out that can't be found or replaced without professional assistance. :) I figure if I have problems with the broken shutter, the fixable one will immediately go to Carol at Flutots or I can always continue to cock the shutter with a hemostat around the cam--my current method.

[Glenn Thoreson]

The Dial Set Compur is about the easiest shutter to work on ever made. The parts should interchange between shutters of relatively the same size.
Remove the screw in the speed dial and lay the parts out in the order they go back, paying special attention to the position of the pin and it's hole in the silver disc. Remove the 3 screws from the trip lever and set it aside. Remove any aperture scale screws and the scale plate, if it has one on the face. Remove the two screws from the front cover. You're in! It will be obvious at that point, what you need to do to change the part. If I remember correctly, it will come right out after you remove the center screw. Take digital pics as you go for reference. Good luck.

[Paul Fitzgerald]

BarryS,

the cam you are looking at is usually the last piece removed. it is attached to the main spring inside of it. when you release the stop you should count have many turns it takes to release so you can pre-set it when you assemble it. the main spring is a long flat coil and should not jump out but it fits to the cam and body ends with a little finger into a slot. it's not fun to change out and easy to put it in upside down.

Have fun with it.

[BarryS]

Gentlemen, I believe I've located the main spring. :eek:

http://img155.imageshack.us/img155/5054/compurshutterspringra0.jpg

Paul--I wish I'd read your post before I removed the cam, but in retrospect, it makes sense that the main spring would be coiled up inside the cam. Fortunately this is my junk shutter, but it's not going to be easy to put in the new cam and get the spring coiled properly.

[BrianShaw]

Barry,
That looks just like a clock or watch spring. I've never seen one like that in a shutter before (but, then again, I've never overhauled a dial-set Compur). Does the post screw into the shutter body? If so, it might be possible to remove it and load the spring onto the shaft and cam as an assembly. For clocks there are "spring winders" to help tension the spring for re-insertion into the barrel. For a lighter spring like this one you can probably wind it on by hand. Then it would be possible to install the cam-spring-post assembly into the shutter. All of this depneds on the ability to remove the post, of course.

If nothing else, you now have a great opportunity to clean and lube the spring.

Good luck. When I get into one of these situations I sweat profusely and vow repeatedly that I'll never take apart another camera shutter! (After fiddling, though, I've generally had enough success that I forget about the vow. If I didn't say it already... good luck!

[BrianShaw]

Check out course # VL-9... I'm tempted to spring for it! (no pun intended.)

http://www.vintage-camera-repair.info/lessons.htm

[BarryS]

Brian--Just checked and the post doesn't unscrew. I think Paul is probably right that the cam is the last piece removed from the front assembly because with the lever arms in place I don't think the spring can be rewound into the cam. That course is pretty reasonable, but I wonder if it's enough to help me tackle the Compur. It doesn't seem *too* complex, but it's way beyond my Packard shutter skill set.

http://img291.imageshack.us/img291/6087/compurshutteropenxo5.jpg

[BrianShaw]

So where is Paul when you need him?

I keep staring at your pictures and it seems that if you remove the lever with the screw in the 7-o'clock position (of picture in post #11) and slide away the "hook" that you unscrewed from the cam... then there should be enough space to re-hook the spring (it looks like a "hook-end" spring; is there a slot in the bottom of the cam to capture the loose end of the spring?) and rewind it until you can get the cam onto the post... and then finish rewinding it.

At this point, I'm sweating vicariously and vowing never to open another shutter... and all I've been doing is looking at your pictures and imagining the guts of my own dial-set Compur that could probably use a good cleaning!

Yesterday I successfully overhauled an Alphax using some on-line repair notes (disassembly only; the author seems to have assumed that if one can get it apart then one can get it back together again). I hope that Valera course has both parts of the operation described!

[BarryS]

I'm not sure I have a tool that can unscrew the bottom lever, but assuming I figure that out, I still may need to remove several levers on the other side of the cam. It's hard to see here because of the photo angle, but the cam is in contact with levers above and below it. I think I'll reassemble and sleep on this one. The Valera course is probably worth a try--too bad I can't just download a PDF. All in all, I'm impressed with the simple robust construction of the Compur. If only they'd made the cocking lever screws a little thicker.

[Paul Fitzgerald]

Hi there,

the post is removed with 4 screws on the face side and drops out the rear after you remove the main plate from the housing. You can lube the center of the cam where the post goes through but the spring should be clean and dry. Attach the spring to the post first and engage the finger. Turn the spring around itself to fit the cam over it (tons of fun here) and turn the cam to engage the other finger. Install from the bottom side and replace the 4 screws. It should take just more than 1 turn to reset the tension and engage the arm that locks it from turning.

The arm that run around the top and has a fork at 9 o'clock covers the eccentric screw that adjusts the gear train for 1 second. Once it is set to run at 1 second, the other times fall into place automatically.

The arm that runs along the bottom has a slot at 9 o'clock, be careful fitting the pin from the selector wheel into it before tightening down the face plate.

Have fun with them.

"I'm not sure I have a tool that can unscrew the bottom lever, "

A pencil eraser usually works well for those screws, just press down while turning counter-clockwise