[rollei_list] Re: Compur Lubricants
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Wed, 12 May 2010 00:30:21 -0700
----- Original Message -----
From: "Roger Beverage" <rbeverag@xxxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Tuesday, May 11, 2010 7:06 PM
Subject: [rollei_list] Re: Compur Lubricants
Yes, a Compur shutter should be able to run dry, but will
run quiter and longer with some very light oil on the
escapement bearings. The older shutters, powered by the
expansion spring that wraps around the lens barrel are make
smoother by a little grease in the grooove in that barrel.
How much oil ? The repairman I learned from said that if
you can see the oil flow from the applicator to the part,
you have put on too much,
There are a couple of ways of applying very small
amounts of oil. One is to use a wire. Watchmakers use
calibrated applicators that are wires with a small ball on
the end that will pick up a certain amount of oil. For
shutters a bit of thin wire will do. Another way is to use a
very fine brush, about the same sort as one would use for
very fine spotting. Put a drop of oil on a hard surface, say
a saucer and brushe it out thin. Then pick up just a little
on the tip of the brush and use that to apply it. The places
that need oil are the trunions of the gears in the regulator
escapement and on the pallet of the escapement. I don't oil
sliding surfaces even though Deckel recommended a little
very light grease on some of them. Grease requires a sliding
surface to be distributed properly and should not be used in
place of oil.
I don't know what the specs were for the greases
recommended by Deckel but there are modern synthetic greases
that will not oxidize or dry up, at least not for a very
long time.
Greases and oils can accumulate dust and become stiff
with time even when they do not become gummy themselves so
its still necessary to clean out and re-lubricate shutters
at intervals even when synthetic lubricants are used.
The proper way to clean and lubricat a Compur shutter
requires removing the regulator. This is not difficult in
most of the shutters but requires the right tools and a
steady hand. There are bearings on both sides of the
regulator and the ones facing the body of the shutter can
not be reached without removing it. There is an adjustment
on most Compurs that sets the slow speeds. It is the
position of the speed regulator assembly in regard to the
release lever for the shutter blades. The assembly is made
so that it can be slid back and forth at one end to exactly
set the spacing. Some shutters are set at 1/10th second,
some at 1 second. Once this is set all the slower speeds
should be close to the marked speeds. The higher speeds will
read slow if a total open time type of shutter speed
indicator is used. The marked speeds are the _effective_
speeds when the aperture is completely open. Since the
blades have a finite opening and closing time (about 1/1000
second for medium sized shutters) the effective exposure
time is less than the time the center of the aperature alone
is open. For most medium sized and Rolei sized shutters the
total open time will be about 80% of the marked speed at
1/500th or 1/400th second and closer at slower speeds. Even
the old dial set Compurs can be made fairly accurate
although the really old ones are likely to have some wear.
Compur shutters have two kinds of springs: the old dial
set and some newer shutters have clock type spiral spring
motors that are made as an assembly. The earlier rim set
type uses a helical spring (like a screen door spring) as
the main shutter and those with speeds faster than 1/200th
second have an additional booster spring for the highest
speed which consists of a wire spring wich is compressed by
the speed cam. This is why the space between the penultimate
and highest speeds is longer than the others plus one can
feel the pressure as the spring is tensioned. The last
version of the Compur, the ones with EVS dials, again have
spiral springs and no booster spring. In these the springs
are a separate part and can be replaced where in the earlier
ones the entire motor assembly must be replaced.
It may help the spiral springs to put some lubricant on
them but they are sliding surfaces so need something that
will take the pressure. They will probably squeeze out most
oils.
Shutters are really quite remarkable, even the crudest
ones like the Ilex are quite accurate and very rugged. The
Compound, an air regulated shutter also made by Deckel, was
made for over seventy years and there are some still going
that are a century old. The are surprizingly accurate and
repeatable when clean.
--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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