Trying to remove a lens in barrel aperture ring without success

[Dwight Anderson]

I've got a 5x7 Herlango view camera with a lens marked L. Clement Paris Double Anastigamat Sextor.

I can't get the aperture ring to turn and there's no set screw in it to remove. The iris is held in with a retaining ring and when that is removed the aperture can be closed by turning the plate while the screw from the external ring stays in place.

The aperture ring has a slot over the screw that goes through the barrel into the iris plate, so maybe it should slide off the barrel, but it's too tight to turn, so unlikely to slide off.

What am I missing?

 

[shutterfinger]

Look around the knurled edge of the ring, there should be a set screw that has to be removed. The pin in your 4th picture may be the end of the set screw incorrectly installed. The barrel will have a slot under the knurled ring with the edge of the aperture operating ring inside the barrel at one end or the other of the barrel slot there will be a hole that the pin end of the set screw fits in.

 

[Dwight Anderson]

There is no set screw in the knurled ring, believe me I've looked. The only thing I've noticed about the ring is the blind slot you can see in picture 5. The pin in the fourth picture is a screw that goes through the slot in the barrel you mentioned, and I believe ends up in the blind slot. The entire iris assembly is loose after the retaining ring is removed and can moved slightly because there is a little play between the set screw and the barrel slot. The set screw appears to be inserted from the outside, under the knurled ring, since there is no slot in the interior end of the screw.

 

[shutterfinger]

Could it be the pin is pressed into the knurled ring from inside the barrel?

 

[Dwight Anderson]

The pin is actually a threaded screw, if it had a slot on the inside end I could try to take it out that way. It's threaded solidly in the iris plate, but just sits loosely in the barrel slot. I was hoping there was something I was missing before I give up.

 

[shutterfinger]

If its a threaded screw it will have some type of slot or hex socket on one end to turn it. Have you tried to turn it with needle nose pliers? Is there a plug over the screw in the ring?
Can you post a picture of the outer ring directly over the screw looking into the outer ring?

 

[Dwight Anderson]

I am imagining that the slot or hex is underneath the knurled ring. It aligns directly with the small slot in the ring show in picture 5. Here is a photo of the ring directly ove the slot, in line with the screw. I would expect the knurled ring has to be held on somehow, while still being able to turn. Is it possible the barrel is in two sections?

 

[shutterfinger]

At this point I would submerge the ring in 90% Isopropyl Alcohol in a sealed container and let it sit over night then allow it to drain/dry before trying to turn it more than 12°. There are likely a pin or two holding the ring in place. Warmed alcohol, 2 or 3 5 minute cycles in succession in an ultrasonic cleaner, will loosen the paint.

 

[Kino]

I would guess that the barrel has to be made in two parts. Since the front part appears to be tapered or flared to make it impossible to slide the aperture ring forward, it would appear this is what holds the ring in place.

Have you tried grasping either end of the barrel and giving it a good twist? If it turns out to be one piece, it shouldn't hurt anything but your hands!

 

[Dwight Anderson]

I'll try soaking it, although I don't want to damage the paint. It is a rather obscure make. Maybe I'll try to see if the barrel is in two parts first. Thanks guys

 

[shutterfinger]

The main areas of shutters that I've had paint to flake off is where skin oils had penetrated the paint and the alcohol was around 100°F.

 

[Dwight Anderson]

Well, I made a little progress. The iris was just being held in by the pin and moved a little within the barrel. So I pushed a little harder on the side away from the pin and the whole iris popped out. The pin actually doesn't have a head, a close look shows it has been clipped off with a snips. The barrel is definitely just one piece, so I'll soak it and see if I can get the knurled ring loose.

 

[Dwight Anderson]

Thanks for the advice on using Isopropyl Alcohol, I soaked it for about 4 hours and the ring turned slowly at first. Another dip for an hour and it turned nice and easy. I also soaked the iris for a while to remove some oil on the blades. The lens is back together and working smoothly. The ring didn't come off the barrel, it's almost as if it sits in a depression.

Now to order some 5x7 plates from J. Lane.

 

[shutterfinger]

Sounds like the ring is a pressed on assembly. I haven't run across this before.