Cold weather and shutter

"Mike" wrote in message
news
I've got a Compur Synchro shutter being CLAed right now.
It worked fine
in warmer weather, but in cold weather, it was getting
stuck.

The repair shop (it came highly recommended) is working on
it, but she
says it keeps failing the "cold test". She hasn't given
up yet however.

To me, it would seem that the cold simply hardens up some
old lubricant.
Would cold weather make springs weaker?

The traditional method of preparing shutters for very
cold weather was to clean out all the lubricant and run them
dry. There are modern synthetic lubricants which maintain
their viscosity over a very wide temperature range. Make
sure one of these lubricants is being used. If the shop
doesn't have any have them clean out _all_ lubricant.
Springs are not made weaker by low temperatures, at least
no temperature encountered in nature.
Worn shutters don't jam up this way. Usually, the symptom
is inconsistent speed.


--
---
Richard Knoppow
Los Angeles, CA, USA

"Richard Knoppow" wrote

Springs are not made weaker by low temperatures, at least
no temperature encountered in nature.

They are by high usage. If it is used a lot, and there is some
residual grease that wouldn't give a new shutter any pause, a
used shutter may bind.

Most significant problems are that way, in that there is more than one
cause. If the grease were fresh but the shutter worn there
would be no problem. If the grease was a bit mucky but the shutter
unused there would no problem. A mucky old shutter ...


--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

"Nicholas O. Lindan" wrote in message
k.net...
"Richard Knoppow" wrote

Springs are not made weaker by low temperatures, at least
no temperature encountered in nature.

They are by high usage. If it is used a lot, and there is
some
residual grease that wouldn't give a new shutter any
pause, a
used shutter may bind.

Most significant problems are that way, in that there is
more than one
cause. If the grease were fresh but the shutter worn
there
would be no problem. If the grease was a bit mucky but
the shutter
unused there would no problem. A mucky old shutter ...


--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

You are talking about metal fatigue which does affect
springs. However, if the shutter is failing to work at low
temperatures its much more likely to be the lubricant than
the spring.
Two main causes for shutters hanging up are gummy
lubricant on the gears of the speed regulator and residual
oil on the shutter blades from improper cleaning or
lubrication. Once reason simply soaking a shutter in solvent
is not a good method is that the dissolved oils can be
deposited on the shutter blades.
In Compur, and many other shutters, the speed regulating
gear assembly is removable and can be cleaned separately.
When really clean they will run dry although the wear rate
goes up. The assembly is usually lubricated with a very
light synthetic oil on the trunnions of the gears and on the
palet of the escapement. Compur also specifies the use of
light grease in a couple of places. Many shutters have two
drive springs. One is the main spring, the other used as a
booster for the top speed only. Kodak Supermatics and compur
shutters are typical. Three different forms of springs are
used in shutters: helical coil springs, spiral "clock motor"
springs, and hair springs. Helical springs are used as main
springs in rim set Compur shutters and Kodak shutters,
Spiral springs in dial set Compur and Compound shutters and
in late Synchro-Compur shutters, and hair springs are used
in Wollensak, Ilex, and other shutters. Hair springs are
used as auxilliary springs in all shutters. Hair springs
have the advantage of being easy to make if they need
replacement.
With out more facts I am only guessing but the symptoms
are pretty indicative of a lubricant problem rather than a
spring problem especially if the shutter works at its higher
speeds when warm.


--
---
Richard Knoppow
Los Angeles, CA, USA

Mike wrote:

With out more facts I am only guessing but the symptoms
are pretty indicative of a lubricant problem rather than a
spring problem especially if the shutter works at its higher
speeds when warm.

Well the shutter is still being worked on. Before she realized
cold-weather problem, she emailed me these speeds:

1 is 1, 2 is 2, 5 is 5, 10 is 10, 25 is 20, 50 is 30,
100 is 60, 200 is 100, 400 is 200.

I guess I'm expecting to hear that the shutter is just worn out. In that
case, maybe I'll try to find a newer Copal because I really did like the
lens.

I think you can just screw the 150mm Symmar lens into a Copal 1, but how
would you go about getting the aperture scale correct?


Who ever is fixing the shutter should be able to make you a new scale.
OTOH if those speeds are constant it wouldn't bother me. Just remember that
200 is 100. The key thing isn't that the numbers match the markings [they
won't] it's that they stay constant.

Nick

--
---------------------------------------
"Digital the new ice fishing"
---------------------------------------

"Mike" wrote in message
news

With out more facts I am only guessing but the
symptoms
are pretty indicative of a lubricant problem rather than
a
spring problem especially if the shutter works at its
higher
speeds when warm.

Well the shutter is still being worked on. Before she
realized
cold-weather problem, she emailed me these speeds:

1 is 1, 2 is 2, 5 is 5, 10 is 10, 25 is 20, 50 is 30,
100 is 60, 200 is 100, 400 is 200.

I guess I'm expecting to hear that the shutter is just
worn out. In that
case, maybe I'll try to find a newer Copal because I
really did like the
lens.

I think you can just screw the 150mm Symmar lens into a
Copal 1, but how
would you go about getting the aperture scale correct?


This could be the result of incomplete cleaning or weak
springs. Springs for some Compur shutters are no longer
available. A good fine mechanic can make springs. Steve
Grimes used to do this but I don't know if the folks who
have his shop now bother.
A proper cleaning of a shutter requires almost total
disassembly. The shutter blades have to be removed and
individually cleaned so that they are completely free of any
residue. The same for the blade actuating ring. This is a
lot of rather tedious work and is not often done.
Even if the drive spring has become fatigued or has been
stretched cold weather should not make it worse. For
instance, do the springs in your car suspension get softer
in cold weather?
You might try calling around to shutter technicians to
find one who either has replacement springs available or can
make them.
I suppose it _is_ possible to wear out Compur shutters
but it takes a lot of use, more than most shutters ever get.
Probably the most vulnerable part are the trunions of the
gears in the speed regulator. The symptom if wear is most
likely to be varying speed.


--
---
Richard Knoppow
Los Angeles, CA, USA

"Richard Knoppow" wrote

cold weather should not make it worse. For
instance, do the springs in your car suspension get softer
in cold weather?

You may be driving on thin ice here, but then you probably don't
get much thick ice in LA.

In cold weather: the battery is weak, the fuel line is
frozen, the radiator is frozen solid and the car overheats,
the engine block is cracked, the air cleaner is full of
snow, there is water and salt all over the wiring and
everything is shorted out, the shock absorbers have turned
to rock, the dashboard has shattered into shards of plastic,
the gear-box grease is like roofing tar, the windshield is
frosted over on the inside, there is an inch of ice on the
outside, the defroster fan has frozen up ...

Everything gets worse in the cold. Maybe it is a spring
though probably not, but it will be _something_.

The argument is:

1) old lube is the problem
2) the problem is _worse_ because the mechanism is worn and weak
3) the problem is _worse_ because of the cold

Or

1) the problem is the cold
2) made worse by old mechanics
3) made worse by old grease

Or

1) the problem is ... blah, blah, blah

Arguing what's on first and who's on second isn't really relevant.

What is significant is that fixing only _one_ of the causes often won't
fix the problem.

"It is never just one thing." "No man is an island." "Takes
two to tango." ... "Things come in threes." etc.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

"Nicholas O. Lindan" wrote:

"Richard Knoppow" wrote

cold weather should not make it worse. For
instance, do the springs in your car suspension get softer
in cold weather?

You may be driving on thin ice here, but then you probably don't
get much thick ice in LA.


I, OTOH, drive on thin ice all the time and
have yet to slide and crash...

In cold weather: the battery is weak, the fuel line is
frozen, the radiator is frozen solid and the car overheats,
the engine block is cracked, the air cleaner is full of
snow, there is water and salt all over the wiring and
everything is shorted out, the shock absorbers have turned
to rock, the dashboard has shattered into shards of plastic,
the gear-box grease is like roofing tar, the windshield is
frosted over on the inside, there is an inch of ice on the
outside, the defroster fan has frozen up ...

Really? I've driven in cold weather for decades and
my fuel line/radiator has never frozen, block never
cracked (unless due to lack of antifreeze) and salt
dosen't corrode the engine wiring (last thing that would
happen, after body rust, even in Detroit.)


Everything gets worse in the cold. Maybe it is a spring
though probably not, but it will be _something_.

The argument is:

1) old lube is the problem

Most likely...

2) the problem is _worse_ because the mechanism is worn and weak

not as likely...

3) the problem is _worse_ because of the cold

yes.


Arguing what's on first and who's on second isn't really relevant.

If ya know who's on first in the first place.
I've had shutters lock up due to cold, and it's
cold a lot here. Had zero temps even in June. It's
the lubricant in my experience.

Nicholas O. Lindan wrote:



Arguing what's on first and who's on second isn't really relevant.


You do realize it's Whos on first, Whats on second ...

no_name spake thus:

Nicholas O. Lindan wrote:

Arguing what's on first and who's on second isn't really relevant.

You do realize it's Whos on first, Whats on second ...

This came up as a category on Jeopardy! the other night. Anyone remember
all the names of the players? (I never even knew them.)


--
God willing, the many crimes of the Bush Administration
will eventually be printed in a nice leatherbound,
multi-volume edition that will look fantastic on my bookshelf.

Nicholas O. Lindan spake thus:

"Richard Knoppow" wrote

Springs are not made weaker by low temperatures, at least no
temperature encountered in nature.

They are by high usage. If it is used a lot, and there is some
residual grease that wouldn't give a new shutter any pause, a
used shutter may bind.

Most significant problems are that way, in that there is more than one
cause. If the grease were fresh but the shutter worn there
would be no problem. If the grease was a bit mucky but the shutter
unused there would no problem. A mucky old shutter ...

"Worn out" shutter? I highly doubt it.

Think about it; let's say the previous user was a really prodigous
photog, who made 15 shots each and every day. Then let's further assume
twice the shutter usage: 30 clicks daily. That's 10,950 clicks per year.
In 20 years, that would total up to 219,000 clicks.

That's *nothing* for a machine like a Compur. It'd take a hell of a lot
more usage than that to "wear out" a shutter.


--
God willing, the many crimes of the Bush Administration
will eventually be printed in a nice leatherbound,
multi-volume edition that will look fantastic on my bookshelf.