Constrution 210/370 converitble Symmar? Compur disassembly?

"Richard Knoppow" <dickburk DeleteThis @ix.netcom.com> wrote in message
news:c8994c6f.0401190602.5f7dcd94@posting.google.com...
 > "John Hendry" <pict DeleteThis @pict.co.uk> wrote in message
news:<9dCOb.160676$JQ1.123906@pd7tw1no>...
  > > Does anybody know what the element construction for a Schneider 210/370
  > > convertible Symmar is? I'm especially interested in the rear element and
  > > whether cemented doublets are present. The rear element has what appears
to
  > > be strange blobby spider shaped patterns in places, and I'm wondering if
its
  > > a surface fungal issue or its in a balsam layer. Photo here..
<font color=green>  > > <a style='text-decoration: underline;' href="http://www.johnhendry.com/rpelf/symmar.jpg</font" target="_blank">http://www.johnhendry.com/rpelf/symmar.jpg</font</a>>
  > >
  > > On a separate issue does anyone know the diasassembly/reassembly
procedure
  > > on a Synchro Compur #1 . I just need to get the cam plate off to address
an
  > > issue with the shutter open lock mechanism. Note sure how to describe
the
  > > vintage of the shutter but here is a shakey snap
<font color=green>  > > <a style='text-decoration: underline;' href="http://www.johnhendry.com/rpelf/compur1.jpg</font" target="_blank">http://www.johnhendry.com/rpelf/compur1.jpg</font</a>>
  > >
  > > As an aside, once the camplate is off, is the slow escapement easily
  > > removable as it is with copal's? It's dragging a bit and could use a
clean
  > > and lube.
  > >
  > > Thanks.
  > > John
 >
 > The f/5.6 Symmar is a Plasmat type lens. The front and rear
 > components are two cemented elements. This appears to be separation in
 > the cement. The lens has a removable front and rear retaining ring.
 > There may be a spacer under the component. I would check it to make
 > sure the "stars" are not fungus on the surface inside the cell rather
 > than being in the cement. When synthetic cement separates it usually
 > looks like large bubbles. If this is fungus clean it off with ammonia.
 > If you look at the center ring of the shutter you will see a cam
 > shaped disc with two holes in it. this is the lock. Use a fine needle
 > nosed pliers to twist this until its flat side faces the retaining
 > ring. The ring is in a bayonet type mount and when the lock is turned
 > the ring will turn 1/3rd turn and come out. When out it will allow
 > removing the cover plate and stop scale. When this is removed you will
 > see the inside part of the speed ring and cam. This can be lifted out.
 > You can get a factory manual for late Compur shutters from Petra
 > Keller at <a style='text-decoration: underline;' href="http://www.camerabooks.com" target="_blank">http://www.camerabooks.com</a> I strongly suggest having a
 > drawing of the shutter before disassembling it.
 >
 > Richard Knoppow
 > Los Angeles, CA, USA
 > dickburk DeleteThis @ix.netcom.com

If I am looking at two cemented elements then it looks as if it is a cement
issue as they don't appear to be that much below the surface, though this
could be on optical illusion. The element is refusing to unscrew from the
barrel despite repeated applications of penetrating oil to the thread, so
it's still hard to give a definitive diagnosis at this time. I bought a
rubber strap wrench to get a better grip on the lens barrel and hopefully
get a touch more torque on it with the lens spanner, but it feels like these
things weren't designed to come apart in a hurry. I did hear that Schneider
at one time offered free recementing of elements showing Schneideritis at
the edges. That must have been a fun job if the battle this one is putting
up against disassembly is anything to go by. It feels as if it wants to
disintegrate rather than break at the thread, so I think I'll let it alone
for a few days to see if the oil will eventually work in. Feels like they
threadlock these with something particularly grippy.

The shutter opening solution had me baffled. I had it as far as releasing
and rotating the black plate but failed to notice the lugs lining up with
cutaways. Anyway, that let me in and I found a bit of foreign debris that
must have sneaked in at the cocking lever slot. So that's at least is one
problem sorted. Thanks for the pointers!
John<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Constrution 210/370 converitble Symmar? Compur disassembly? 

"John Hendry" <pict.TakeThisOut@pict.co.uk> wrote in message
news:8w0Pb.180496$ts4.12032@pd7tw3no...

(snip)
 > If I am looking at two cemented elements then it looks as if it is a
cement
 > issue as they don't appear to be that much below the surface, though this
 > could be on optical illusion. The element is refusing to unscrew from the
 > barrel despite repeated applications of penetrating oil to the thread, so
 > it's still hard to give a definitive diagnosis at this time. I bought a
 > rubber strap wrench to get a better grip on the lens barrel and hopefully
 > get a touch more torque on it with the lens spanner, but it feels like
these
 > things weren't designed to come apart in a hurry. I did hear that
Schneider
 > at one time offered free recementing of elements showing Schneideritis at
 > the edges. That must have been a fun job if the battle this one is putting
 > up against disassembly is anything to go by. It feels as if it wants to
 > disintegrate rather than break at the thread, so I think I'll let it alone
 > for a few days to see if the oil will eventually work in. Feels like they
 > threadlock these with something particularly grippy.

I had another go at releasing the retaining ring on the lens just now and it
decided to surrender. Having got the cemented pair of elements out, the
problem is definitely with cement separation, which leads me to how does one
go about separating the elements and recementing?I've read the info at
Summers Optical and SK Grimes and I'd like to give it a go. However I can
find no info about the release procedure for synthetic cements (I would
think it would be synthetic rather than balsam). Just heat it up? The
cemented pair looks like they have been ground together with parallel sides
of decent width (3/8" maybe) so I'm pretty sure I can use the edges to
physically reallign the optical centres fairly accurately. Does anyone know
what solvents are killer for cement but safe for coatings, or is there a
good tip for protecting coated surfaces whilst cleaning the old cement off?
As a first attempt at recementing elements would I be better off using
canada balsam or would a polyester or uv cure cement be equally suitable,
assuming I might have to backtrack and start again. Needs to be reversible
at any rate. Any advice appreciated.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Constrution 210/370 converitble Symmar? Compur disassembly? 

 > I had another go at releasing the retaining ring on the lens just now and
it
 > decided to surrender. Having got the cemented pair of elements out, the
 > problem is definitely with cement separation, which leads me to how does
one
 > go about separating the elements and recementing?I've read the info at
 > Summers Optical and SK Grimes and I'd like to give it a go. However I can
 > find no info about the release procedure for synthetic cements (I would
 > think it would be synthetic rather than balsam). Just heat it up? The
 > cemented pair looks like they have been ground together with parallel
sides
 > of decent width (3/8" maybe) so I'm pretty sure I can use the edges to
 > physically reallign the optical centres fairly accurately. Does anyone
know
 > what solvents are killer for cement but safe for coatings, or is there a
 > good tip for protecting coated surfaces whilst cleaning the old cement
off?
 > As a first attempt at recementing elements would I be better off using
 > canada balsam or would a polyester or uv cure cement be equally suitable,
 > assuming I might have to backtrack and start again. Needs to be reversible
 > at any rate. Any advice appreciated.

I eventually got the retaining ring for the front element free. I made a
custom lens spanner from 3/16"x1" mild steel bar and ground out the
appropriate slots and blades using a dremel. Took 20 mins and wasn't too
hard to get a tool that fitted well and gave good purchase. Inititially I
had great difficulty getting the retaining ring to budge and tried applying
and leaving penetrating oil overnight with no success. I had been holding
the lens in my hand whilst attempting to loosen the ring with my spanner, so
I bought a rubber banded strap wrench to hold the lens barrel and the
combination of this and the homemade wrench gave me sufficient purchase to
loosen off the thread. Richard Knoppow suggests acetone may be an
alternative to oil to get into the thread and loosen it, and that brass is
an alternative material for making the spanner.

Anyway, I now have the elements out and have decided to recement them
myself. First problem is how to separate them. I think firstly I'll try
immersing in boiling water, and if that doesn't work the next apparent
solution seems to be a proprietory release fluid sold by summers optical...

<a style='text-decoration: underline;' href="http://www.emsdiasum.com/Summers/optical/cements/decementing/decementing.html#decement" target="_blank">http://www.emsdiasum.com/Summers/optical/cements/decementing/decementi...html#de</a>

You immerse the lens in this stuff and let it boil at 340 deg F. Why can't
you just use canola oil? Intuitively it would seem to be a temparature thing
(rather than chemical) to get the cement to lose its grip and canola is
readily available and has a higher boiling point (500 d F?)
source.. <a style='text-decoration: underline;' href="http://www.libertynatural.com/msd/102.htm" target="_blank">http://www.libertynatural.com/msd/102.htm</a>


Next thing would be what solvent to use to clean any remaining cement from
the surfaces. Is acetone safe for lens coatings, or do you have to be
religiously careful about getting it on any of the uncemented surfaces?

Once the elements are clean, what to recement with? Being a first time
novice, canada balsam has appeal but perhaps modern synthetics are a better
choice. My only criteria here is that the cement should have a refractive
index close to that of the original cement (same as the glass?), be durable
and easy to work with, and
above all be removable if I make a mistake. What specific cement product do
people recommend?
Other than the above, I think, I'm happy with the rest of the process, as
outlined here..

<a style='text-decoration: underline;' href="http://www.emsdiasum.com/Summers/optical/cements/manual/manual.html" target="_blank">http://www.emsdiasum.com/Summers/optical/cements/manual/manual.html</a>
and here..
<a style='text-decoration: underline;' href="http://www.skgrimes.com/popsci/index.htm" target="_blank">http://www.skgrimes.com/popsci/index.htm</a>"

Thanks,
John<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Constrution 210/370 converitble Symmar? Compur disassembly? 

I have a convertible Symmar 180/315 showing a similar pattern (off center)
in the rear element. I think it is a problem with a layer between cemented
elements. It does not seem to affect the image.

Bas Hoeben (the Netherlands)

John Hendry <pict RemoveThis @pict.co.uk> wrote in message
news:9dCOb.160676$JQ1.123906@pd7tw1no...
 > Does anybody know what the element construction for a Schneider 210/370
 > convertible Symmar is? I'm especially interested in the rear element and
 > whether cemented doublets are present. The rear element has what appears
to
 > be strange blobby spider shaped patterns in places, and I'm wondering if
its
 > a surface fungal issue or its in a balsam layer. Photo here..
<font color=purple> > <a style='text-decoration: underline;' href="http://www.johnhendry.com/rpelf/symmar.jpg</font" target="_blank">http://www.johnhendry.com/rpelf/symmar.jpg</font</a>>
 >
 > On a separate issue does anyone know the diasassembly/reassembly procedure
 > on a Synchro Compur #1 . I just need to get the cam plate off to address
an
 > issue with the shutter open lock mechanism. Note sure how to describe the
 > vintage of the shutter but here is a shakey snap
<font color=purple> > <a style='text-decoration: underline;' href="http://www.johnhendry.com/rpelf/compur1.jpg</font" target="_blank">http://www.johnhendry.com/rpelf/compur1.jpg</font</a>>
 >
 > As an aside, once the camplate is off, is the slow escapement easily
 > removable as it is with copal's? It's dragging a bit and could use a clean
 > and lube.
 >
 > Thanks.
 > John
 >
 >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Constrution 210/370 converitble Symmar? Compur disassembly? 

"Bas Hoeben" <jahoeben.TakeThisOut@worldonline.nl> wrote in message
news:40104675$0$41756$5fc3050@dreader2.news.tiscali.nl...
 > I have a convertible Symmar 180/315 showing a similar pattern (off center)
 > in the rear element. I think it is a problem with a layer between cemented
 > elements. It does not seem to affect the image.
 >
 > Bas Hoeben (the Netherlands)

Mine were all over the center portion of the lens and quite large, and it
was in the cement layer, not the rear surface of the doublet. I think there
would be noticeable degradation in my case. Maybe not, but I'm committed
now - the elements decemented after about 20mins simmering in near boiling
water, so I have them cleaned up and ready for rejoining when the cement
arrives.

John<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Constrution 210/370 converitble Symmar? Compur disassembly?