HOW TO TAKE LENSES OFF A COMPUR-P SHUTTER?

Dr. Slick

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Sep 26, 2003, 6:16:22 AM9/26/03

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Hi,

I'm a newbie that just bought a Crown Graphic Special, with a
135mm Schneider lens. The shutter is way slow at one second,
sometimes even getting stuck. And i'm sure that the fast speeds are
off too.

I've been reading that some people have had success emmersing the
whole shutter in lighter fluid, after taking the lenses off, without
having to take the whole thing apart.

If a CLA is going to cost me around $80-100, i think i would like
to at least try this first. That way, if it seems to work smoothly
again, i could just get a $20 "readout" of the actual shutter speeds,
and use these values.

How do you take the lenses off? There seems to be only a screw on
the back lens thread that has four "notches" in it, and i don't have
the special tool for removing this. Does the front lens unscrew at
all? I'm afraid to break something. Perhaps i should just get the
CLA from a professional?

At any rate, perhaps i don't need to do anything, because i really
just wanna do copy work of my paintings and artwork, and the first guy
that did this for me did so with a manual shutter (bulb mode), and
shutter speeds of around 5-8 seconds or so, which he did manually with
a stopwatch in his other hand. So either he used really slow chrome,
or really small apertures, or both.

So perhaps i don't need to fix the mechanical shutter at all, but
i'd still like to use it if i can.

Thanks for any advice you can give me.

Slick

Richard Knoppow

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Sep 26, 2003, 2:40:05 PM9/26/03

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"Dr. Slick" <radi...@aol.com> wrote in message
news:1d15af91.0309...@posting.google.com...

The slotted ring holds the lens elements in the lens cell.
Leave it alone. The cells unscrew from the shutter. You
should be able to remove them with your fingers.
The problem with immersing the whole shutter in solvent is
that it may spread oils around, especially depositing them
on the shutter and diaphragm blades. Real cleaning requires
some disassembly of the shutter and several successive baths
in solvent. Its also necessary to lubricate some parts of
the shutter. A very small amount of lubricant is used.
Generally its synthetic watch oil, an oil which does not
migrate from where its applied and has a long life before it
begins to stiffen up.
The slow speeds are controlled by a clockwork gear
mechanism. These often slow down or even freeze up because
the oil on them has congealed with age. Its sometimes
possible to get them to come up to speed by simply applying
a small amount of fine oil to them but you have to get into
the shutter first.
Learning to clean shutters is not too difficult but you
really need a shutter that isn't being used to practice on.
$75 is about the going rate for shutter cleaning and
lubricating. There really are not any adjustments in most
shutters. Sometimes the fastest speeds are slow because the
drive spring or springs are stressed and sometimes because
there is some dirt on the shutter blades. The latter should
NEVER be lubricated.
Beyond this the highest speed on a shutter is really a bit
of wishful thinking. Its the _effective_ speed for the
maxumum aperture of the shutter. The total open time speed,
which is what most testers measure, is genrally only about
80% of this.
The Press Compur differs from the standard Compur in that
it has a "press focus" button or lever for holding the
shutter blades open for focusing with out shifting the speed
control to Time.
These are very rugged shutters and can generally be
brought up to specs.
There are some books available on shutter work. Try
http://www.craigcamera.com for starters.
--
Richard Knoppow
Los Angeles, CA, USA

Bob G

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Sep 26, 2003, 3:08:20 PM9/26/03

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>I've been reading that some people have had success emmersing the
>whole shutter in lighter fluid, after taking the lenses off, without
>having to take the whole thing apart.

DON'T DO IT!!

Lighter fluid is BAD

It might work for a while, but it will leave a residue all over your shutter as
it evaporates and it will eventually jam it tight

The proper liquid to use, if you're going to do such a primitive thing as to
immerse the whole shutter in it, is some variation of trychloro-ethylene

Two cautions: first, any plastic parts in your shutter wil be destroyed, and,
second, trychloro is a carcinogenic

Good luck,

Bob G

David Nebenzahl

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Sep 26, 2003, 3:25:00 PM9/26/03

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On 9/26/2003 12:08 PM Bob G spake thus:

Sorry, what you've just said is simply not true. (Except the part about TCE
being a dangerous carcinogen, which is true: you don't even want to *think*
about using this stuff.)

"Ronsonol" is one of the most widely-used solvents for cleaning shutters and
other precision mechanisms. Of course, as Richard K. has pointed out, you
don't just dunk the whole shutter in it: you've got to disassemble it first.
But lighter fluid is an excellent solvent: it has a low enough boiling point
that it will evaporate nicely and not leave any oily residue over the moving
parts.

I use low-odor paint thinner myself, which is similar to Ronsonol (which is
naptha), as it doesn't stink, is cheap, and does the job well. The main thing
is to make sure to get all of the gunk off in the solvent, and then to make
sure all the solvent is removed or dried before applying any lubrication.

--
Why isn't "phonetic" spelled fonetically?

Radio913

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Sep 26, 2003, 3:45:27 PM9/26/03

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>Sorry, what you've just said is simply not true. (Except the part about TCE
>being a dangerous carcinogen, which is true: you don't even want to *think*
>about using this stuff.)
>
>"Ronsonol" is one of the most widely-used solvents for cleaning shutters and
>other precision mechanisms. Of course, as Richard K. has pointed out, you
>don't just dunk the whole shutter in it: you've got to disassemble it first.

Ok, how do you disassemble a Synchro-Compur-P? How do you take the lenses
off? Is there a website or manual i can buy that explains in detail?

Slick

Richard Knoppow

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Sep 26, 2003, 6:17:53 PM9/26/03

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"Radio913" <radi...@aol.com> wrote in message
news:20030926154527...@mb-m15.aol.com...

There may well be a web site but I don't know of it.
Lenses are mounted in most shutters in screw mount cells.
The cell is the metal barrel that contains the glass lens
elements. The glass parts do not have to be removed from the
cell.
The cell mearly screws into the front and back of the
shutter. Often, the shutter will have adaptor tubes. These
are simply short tubes threaded on each end. One end is
threaded ito the shutter, the ohter end is threaded to take
the lens cell.
Sometimes cells are hard to remove. Its helpful to use a
gripper like a rubber glove go give your hands better
traction. No tool should be necessary. In some cases the
shutter will have to be removed from its lens board to get
the back cell off. It depends on how much of the cell sticks
out.
Ed Romney has some elementary books on camera repair. Not
the best written but unique and valuable for getting
started. See: http://www.edromney.com
Other sources are the reprint books on shutters and
cameras from John S. Craig and Petra Keller. Both are very
reliable dealers. John Craig is at:
http://www.craigcamera.com Petra Keller is at:
http://www.camerabooks.com
For working on shutters you will need a set of jewelers
screwdrivers. Servicable sets can even be found in the
grocery store but a hardware store is likely to have better
quality.
You need fine tweezers. Ideally, this should be Dumont
pattern made of non-magnetic stainless steel. They are
widely available surplus for not much. In liu of these one
can use regular eyebrow plucker tweezers.
Work in a box so that you won't loose any parts. Pill
containers are good for holding parts while you work. Small
screws, etc., can be stuck on a piece of sticky tape to make
them easier to find.
It is VERY helpful to have drawings and photos of the
shutter so you will know where things go. If you have a
digital camera take pictures while you work. Don't rely on
memory.
Suitable oil can be had from hobby shops who sell model
railroad stuff. I use a brand called LeBell. It comes in
three grades, use the thinnest. Another good oil but harder
to find is Nyoil, do a Google search to find sources. The
oil is applied to only a few places, mainly the trunions of
the gears and to the pallet of the excapement. A very small
amount is needed. Apply with a toothpick or use a very fine
brush. To use the brush put a drop or two of the oil on a
saucer and brush it out. Then pick up just a little on the
tip of the brush and put it where you want it. Watchmakers
use special oil dispensers but for occasional use you don't
need such fancy tools.
The best solvents are pure naptha. Ronsonol lighter fluid
works well. Hardware store naptha works for rough cleaning
but my not be pure enough to dry without leaving a residue.
You can dip the shutter in the solvent and blow it out
with canned air. You can also make a simple vapor degreaser
by putting some solvent in the bottom of a jar, putting the
shutter on a bit of screen and closing the top. Let this sit
in a warm place for a while. Then open and remove the
shutter.
Another solvent which works well is pure Isopropyl
alcohol. 99% Isopropyl is available in most drug stores. Do
NOT use rubbing alcohol, it has too much water in it. The
use of both Alcohol and naptha sequentially will insure
removal of all grease and oils from the shutter parts.
Shutters will often work dry (no lubricant) if very clean
and some shutters (Ilex for instance) are intended to run
dry. However, the life of the shutter and its speed
consistency will be better if properly lubricated. Some
shutters need additional lubrication. A very light dose of
Lubriplate to the speed ring for instance but in general
grease is not used in shutters. No lubricant should EVER be
applied to shutter blades or diaphragm blades. They must be
scrupulously clean. Even a very small amount of residue on
shutter blades will cause enough drag to significantly slow
down the shutter.
Extremely dirty shutters must be partially disassembled
to be cleaned adequately. Occasionally one must be
completely disassembled but this is a major job and most
shutters are difficult to reassemble. You definitely need
drawings and photos to do this. For the most part removing
the lens cells, front cover, and perhaps the speed ring, are
all that is necessary.