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  1. #1

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    Help with Kodak Flash Supermatic Shutter?

    I am in the process of overhauling a Kodak Monitor Six-20 with a Flash Supermatic shutter, trying to get the camera ready for 620 camera day which is coming up in a little over a week. Today I was so pleased to finally get the shutter back together after a long and rather tortuous CLA (torturous because it is a new shutter to me and I don't yet have a manual). Everything seemed to be looking and sounding great, and in fact could tell that the slow speeds were right on the money. But unfortunately my shutter speed test showed that the fast speeds are slow, falling behind by as much as 1-1/3 stops at the top end. Any suggestions? Is there something which is perhaps not engaging properly, or maybe some adjustment I have missed?

    For reference, here are my numbers, and also a plot showing the error in stops (measurement resolution is 1/6 stop):
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    Thanks.

    Jeff
    Last edited by Denverdad; 06-10-2014 at 11:59 PM. Click to view previous post history.

  2. #2

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    Yeah, typical. I don't think they were right for more than a week after they left the factory. Annoying, isn't it? That high speed spring isn't worth a damn. What we have here is wear introducing just enough slop that parts shift laterally in their movements, and additively they foul up everything. Springs get weak, etc. Good luck with that.

  3. #3

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    Well that's not encouraging to hear!
    Do I at least understand correctly that the high speeds on this shutter result from the pallet being disengaged from the low speed escapement, but with the escapement gears still engaged? That's what it looked like to me. Also, can you confirm - is the high speed cam designed to come into play ONLY at the highest speed?

    As for springs, I have had good luck with very simple shutters bending or re-making them to restore (or even increase) speed. But it could be trickier with a "real" shutter since it is not just a single speed I am trying to get right.

  4. #4

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    The high speed spring come into play only at 1/400. I can't clearly recall the configuration, but if incorrectly installed the "peg" that catches the leg of that springs will pass by it and not catch-and-engage. If your shutter is a Wollensak-style rim set, then filing of the step cam is a remedy. But to me, it is a false remedy IMO. That is to say if you have to resort to that, then the shutter parts are obviously worn enough that "lateral" shift in the motion of parts is additively causing slow movement. In other words, there is only so much you can do. I'm convinced that an iris shutter is one of the poorer inventions of man, but they exist only because there IS nothing else. I think they wore out after the first 5 rolls of film, and have been inaccurate ever since. Or something. I think an iris shutter would be a watchmaker's nightmare. You can spend weeks in experimenting, bending new springs, re-fabricating parts worn by the measurement of a germ's hair, and end up in an asylum before making one behave the way it's supposed to. Sometimes you have to say "it is what it is". Try not to get too annoyed when you have to open it up again for the 40th time.
    Remember, I'm no shutter expert by a long shot. I'm just a fellow who refuses to be just a regular boob.

  5. #5

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    Be sure the bottom of the HS spring is not between the 2 parts, but against it's appropriate notch. even then, there is no 1/400. Probably never was. Top speed will never be more than 1/250 unless you put a turbo supercharger and a rocket engine on it. Be glad to get 1/200 and below The bitter truth. Congratulations. 1/400 is now your 1/200th or 250th if you're lucky. And 1/200th is your official 1/150th. When you've had the shutter apart for umpteen dozen times you will realize this.

  6. #6

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    Tom, thanks for the information, suggestions, ...and empathy! I reluctantly removed the lenses from the shutter last night and tore into it for a follow-up inspection. One thing I saw was that the high speed spring and cam appear to be doing just what they are supposed to - contact is made just above the 200 mark on the cam ring thingy (only at 400 does the boost kick in), and the spring is being wound normally when this occurs without binding or anything like that. Also, checking the numbers above, the duration at 400 is in fact half of what it is at 200, so that is consistent. Without the high speed mechanism engaging, the speed would have been the same and the error at the highest speed would have continued its trajectory to an even higher value, instead of leveling off. So all in all, I think that part of the shutter is actually OK!

    But I discovered a curious thing last night that I hadn't noticed before. At one of the shutter blade locations, there are actually two blades, so it basically appears as if that blade were doubled. There are a total of 6 blades instead of 5, and at the double blade location the adjacent blade actually slides between these two. Is that normal for this shutter? If not (perhaps an assembly error at the factory?) it might explain the slowing of speeds on the high end. Does anyone know? I can take a picture of this later if it helps to explain what I am seeing.
    Last edited by Denverdad; 06-11-2014 at 12:16 PM. Click to view previous post history.

  7. #7
    Hatchetman's Avatar
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    I recently had a Supermatic 800 shutter CLA'd by Paul Ebel. It was his opinion that the fast shutter speeds never did, in fact, reach those speeds. Now the shutter is accurate to 1/100. Then 1/200 is also 1/100. 1/400 is actually 1/200 and 1/800 is actually 1/400, which is pretty good. I just need to remember that when using.

  8. #8

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    Yeah, 2 is typical, on a Betax shutter anyway. I didn't know they put 2 on the Supermatic. Leave it be, it's no mistake. One is on top of the blade stack and 1 at the bottom of the stack. This is to be sure the shutter really is light-proof when it's closed. Otherwords, light would "leak around" the next lowest blade from the top of the stack without it, and the shutter would be worthless for walking around in the daylight without a lens cap.

  9. #9
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    Click image for larger version. 

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    free to save the jpegs to your hd.
    The double shutter blade is to ensure a light tight shutter. A few shutter makers use the system so it is not uncommon.
    Slow high end speeds are a result of running the shutter too long between CLA's. A low use or cla done when the shutter was between .3 and .5 stop off usually return to .5 stop off at 200 and 400.
    Shutters run until they were 1 stop off to quit working only come back to in tolerance up to 100 with faster speeds 1 to 2 stops off.
    Last edited by shutterfinger; 06-11-2014 at 08:33 PM. Click to view previous post history.

  10. #10

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    Quote Originally Posted by shutterfinger View Post
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    free to save the jpegs to your hd.
    The double shutter blade is to ensure a light tight shutter. A few shutter makers use the system so it is not uncommon.
    Slow high end speeds are a result of running the shutter too long between CLA's. A low use or cla done when the shutter was between .3 and .5 stop off usually return to .5 stop off at 200 and 400.
    Shutters run until they were 1 stop off to quit working only come back to in tolerance up to 100 with faster speeds 1 to 2 stops off.
    Thanks shutterfinger - I was hoping you would chime in!
    Very interesting about the double blades - I had never seen that before but I guess the previous shutters I have worked on simply didn't have this feature.
    If I am hearing you right regarding neglected shutters (infrequently serviced or unused for a long period of time), it is rather disappointing to know that even with an expert CLA the top speeds might not be recoverable to any closer than a stop or two. It seems to me that many if not most vintage folders that one might buy fall into this category. I take it that this is more than just a case of worn springs which could theoretically be replaced? Is it more an issue of wear to contact surfaces such as pins and cams and that sort of thing?

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