30" Artar very stiff aperture. How to fix? OIL?!!!

[Tin Can]

My very nice 30" Artar has a very stiff aperture. It is nearly impossible to adjust. These are not worth that much, not like Red Dot Artars. I do want to use it.

The aperture blades look fine and not binding. I think it is a problem with the aperture ring binding.

Would a tiny drop or 2 of penetrating oil to the suspect area be a good or bad thing to do?

[BrianShaw]

I've faced that situation twice. Here is my experience: (1) forcing it will break things. I broke the adjusting knob off of an old brass lens by trying to force it. Bad me. (2) a drop of two of lighter fluid is much better than oil. A solvent loosens up the gunk and hopefully redistributes that gunk thinner than before, leaving the aperture more functional than it was previously. The lgihter fluid will evaporate whereas a penetrating oil won't.

Summary: The oil idea is a bad one.

[Tin Can]

Good idea and I even have some. Trying it now. Reporting later. Thanks!

Any other hints?


I've faced that situation twice. Here is my experience: (1) forcing it will break things. I broke the adjusting knob off of an old brass lens by trying to force it. Bad me. (2) a drop of two of lighter fluid is much better than oil. A solvent loosens up the gunk and hopefully redistributes that gunk thinner than before, leaving the aperture more functional than it was previously. The lgihter fluid will evaporate whereas a penetrating oil won't.

Summary: The oil idea is a bad one.

[BrianShaw]

Only one additional hint. Small drop(s) of lighter fluid or equivelent solvent. Small drops can be repeated wheras flooding may be too much and spread gunk too far.

[BrianShaw]

Oh.. may be one more hint. Let remove the lens cells and let the solvent fully evaporate before reassembling.

[jcoldslabs]

A solvent loosens up the gunk and hopefully redistributes that gunk thinner than before, leaving the aperture more functional than it was previously. The lgihter fluid will evaporate whereas a penetrating oil won't.

Good advice. I was able to free up a very stuck aperture ring on an old Wollensak lens barrel using the lighter fluid trick.

Jonathan

[blueribbontea]

I tried lighter fluid on a 21 inch eastman and it loosened up while there was still some moisture but then stiff again. The grease had hardened with accumulated dirt and needed to be removed, not just softened. That required dissassembly. It's working fine now.

[Jim C.]

You need to flush the gunk out, decades of finger oils, oiling, moisture, and dirt makes a nasty "snot" in the aperture mechanism,
redistributing it isn't a very good solution as blueribbontea found out.
I've used DeoxIT D series contact cleaner to flush the crud out. I've ordered it from McMaster ( they don't mention brands, my pet peeve with them )
but it can be ordered from Caig directly - http://store.caig.com/s.nl/sc.2/category.292/.f
It does leave a ever so slight residue, but that can be flushed off with naptha or lighter fluid, I seem to recall Caig having a version that cleans only.

[Bernice Loui]

Artar, non red dot lenses are often under rated. Some are coated, some are not. In the pile is an Artar, non red dot serial number 77xx... that is coated and excellent performer. They often have much lower resale value due to the perception Artar is not coated and lesser than Red Dot Artars.. which is simply not true. It is individual lens dependent.

If the lens barrel is constructed in the typical Goerz style, the aperture ring stays in place using very fine threads.

*The cure for the stuck aperture ring is to look for the screw-pin that operates the iris.

*Once it has been located on the aperture ring, carefully mark it's position relative to the lens barrel and using a high quality, proper fitting screwdriver remove it from the aperture ring.

*Dampen a Q-tip with just enough low viscosity oil to apply oil around the circumference of the aperture ring.

*Then carefully work the aperture ring free using CW & CCW motion.

*Once the aperture ring has eased enough to move some what freely, remove it completely off the lens barrel by rotating it CCW.

*Note the number of turns required to remove the aperture ring.

*Upon removal of the aperture ring from the lens barrel, clean the internal threads with 99% or greater Isopropyl alcohol, do the same to the threads on the lens barrel. Do not use too much Isopropyl alcohol as it will enter the iris inside the lens barrel.

*When the threads are clean down the base of the threads, apply a small amount of synthetic grease (Dupont Krytox) not heavier than NLGI-2 to the treads.

*Install the threaded aperture ring back on to the lens barrel body with the same number of turns as used for removal.

*line up the screw-pin location that operate the iris to the lens body.

*Install the screw-pin back into the aperture ring and seat the skew. If the screw does not engage the starting threads inside the aperture ring, very slightly rotate the aperture ring to line-up the screw-pin location to the iris operating slot inside the lens barrel.


It is dirt, grease turned to clay and other grit inside the aperture ring threads that cause this problem. The difference cleaning out and proper lubrication on the threads makes a "black -vs- white" difference in how the aperture operation of these Goerz lens barrels.



Bernice




My very nice 30" Artar has a very stiff aperture. It is nearly impossible to adjust. These are not worth that much, not like Red Dot Artars. I do want to use it.

The aperture blades look fine and not binding. I think it is a problem with the aperture ring binding.

Would a tiny drop or 2 of penetrating oil to the suspect area be a good or bad thing to do?

[Tin Can]

Great detailed advice. I have done nothing yet, as i went for a long walk on our first nice day in 5 months, came home and fell asleep.

I have the right screwdriver, I can count turns and i have that grease.

This will be great when it works.

I like Artars and have a few, both Red Dot and not and in studio shooting, I see no difference.



Artar, non red dot lenses are often under rated. Some are coated, some are not. In the pile is an Artar, non red dot serial number 77xx... that is coated and excellent performer. They often have much lower resale value due to the perception Artar is not coated and lesser than Red Dot Artars.. which is simply not true. It is individual lens dependent.

If the lens barrel is constructed in the typical Goerz style, the aperture ring stays in place using very fine threads.

*The cure for the stuck aperture ring is to look for the screw-pin that operates the iris.

*Once it has been located on the aperture ring, carefully mark it's position relative to the lens barrel and using a high quality, proper fitting screwdriver remove it from the aperture ring.

*Dampen a Q-tip with just enough low viscosity oil to apply oil around the circumference of the aperture ring.

*Then carefully work the aperture ring free using CW & CCW motion.

*Once the aperture ring has eased enough to move some what freely, remove it completely off the lens barrel by rotating it CCW.

*Note the number of turns required to remove the aperture ring.

*Upon removal of the aperture ring from the lens barrel, clean the internal threads with 99% or greater Isopropyl alcohol, do the same to the threads on the lens barrel. Do not use too much Isopropyl alcohol as it will enter the iris inside the lens barrel.

*When the threads are clean down the base of the threads, apply a small amount of synthetic grease (Dupont Krytox) not heavier than NLGI-2 to the treads.

*Install the threaded aperture ring back on to the lens barrel body with the same number of turns as used for removal.

*line up the screw-pin location that operate the iris to the lens body.

*Install the screw-pin back into the aperture ring and seat the skew. If the screw does not engage the starting threads inside the aperture ring, very slightly rotate the aperture ring to line-up the screw-pin location to the iris operating slot inside the lens barrel.


It is dirt, grease turned to clay and other grit inside the aperture ring threads that cause this problem. The difference cleaning out and proper lubrication on the threads makes a "black -vs- white" difference in how the aperture operation of these Goerz lens barrels.



Bernice

[Bernice Loui]

Oh, remove the lens cells before working on the lens barrel.

This has been done to every Goerz lens barre in the pile, the different this procedure make is pretty amazing.

On a very few of the Goerz barrels with stuck or sticking aperture rings, cleaning of the iris is required to get it working as new. Cleaning of the iris blades is MUCH more involved and required if the blades have become contaminated with oil as this will affect iris operation and possibly drip oil on to the lens cells.


Bernice

[Tin Can]

Well this will be my baptism by fire. I hope to leave the blades alone. They are dry and moving well.

I am quite handy with all mechanical things. But I have weak hands from using power tools too long...

If this goes well, I will begin working on my broken shutters, that I bought specifically for educational purposes and parts.

Fortunately I have a 25" Process Cooke for stand in, and it's faster.


Oh, remove the lens cells before working on the lens barrel.

This has been done to every Goerz lens barre in the pile, the different this procedure make is pretty amazing.

On a very few of the Goerz barrels with stuck or sticking aperture rings, cleaning of the iris is required to get it working as new. Cleaning of the iris blades is MUCH more involved and required if the blades have become contaminated with oil as this will affect iris operation and possibly drip oil on to the lens cells.


Bernice

[Bernice Loui]

This aperture ring cleaning process can be applied to Kodak, Schneider and others as most lens barrels are made this way.

Kodak lens barrels with spring detents have a screw pressing on a coil spring with a steel ball on the other end of the spring that produces the f-stop detents located on the lens barrel.

Black aluminium Schneider lens barrels with detents have a leaf spring inside the lens barrel which presses a steel ball against holes on the aperture ring to produce the f-stop detents.

More often than not, it is dirt, grit, old dried up lubricant and.. that causes the aperture ring problems. A proper cleaning makes all the difference in it's operation.



Bernice

[Tin Can]

I got it apart without trouble.

The aperture itself moves easily when tested with a slight nudge.

I will be putting it together tonight.

There is major brass wear next to the area, which I think must have been caused by a aperture flag or lever as seen on some of these process lenses in old pictures, as installed in copy cameras. The wear seems to not have any bearing on existing function.

113589113590113591

[Dan Dozer]

I've had lenses before with aperatures that had internal problems and had nothing to do with cleaning. One Dahlmeyer in particular had an internal nut that was tightened too tight, one that had a screw tightened too tight. If you can get things apart and the aperature moves fine, then it might more likely be a slight mechanical adjustment that you need to tinker with to free things up.

[Bernice Loui]

Thread look good. Looks like there was an add on to the aperture ring that scrapped on the lens barrel for years and years.

It is possible to test the iris operation with the aperture ring removed.

Find the slot on the iris ring, mark it's position. Then put a metal rod that fits the iris slot and try moving the iris blades. They should operate smooth and freely. If there is binding, there could be oil on the iris blades or the iris retaining ring is out of adjustment. The iris is usually OK, but it is possible the iris can have problems.... which is more involved to repair.

Curious to know how this all worked out.



Bernice




I got it apart without trouble.

The aperture itself moves easily when tested with a slight nudge.

I will be putting it together tonight.

There is major brass wear next to the area, which I think must have been caused by a aperture flag or lever as seen on some of these process lenses in old pictures, as installed in copy cameras. The wear seems to not have any bearing on existing function.

[Tin Can]

Bernice,

Success!

I did exactly as you instructed and it now works smoothly and as well as any other much newer lens I have.

The key was careful disassembly and counting the 26.5 turns it took to remove the control ring. I learned a lot. I had to do this all without glasses as I can't see tiny things with them.

I carefully cleaned the threads and any muck I could retrieve from the slot. Patience is a virtue, that's why I did it over 2 days, so I would not rush.

I used a high grade PTFE Food Grade lube, good for -45F to 450F, which I applied only to the ring in very small amounts and then wiped off the lube, leaving a tiny amount in the ring's thread grooves.

I am very happy with this lens now and will be using it extensively.

Thank you so much Bernice!



Thread look good. Looks like there was an add on to the aperture ring that scrapped on the lens barrel for years and years.

It is possible to test the iris operation with the aperture ring removed.

Find the slot on the iris ring, mark it's position. Then put a metal rod that fits the iris slot and try moving the iris blades. They should operate smooth and freely. If there is binding, there could be oil on the iris blades or the iris retaining ring is out of adjustment. The iris is usually OK, but it is possible the iris can have problems.... which is more involved to repair.

Curious to know how this all worked out.



Bernice

[ScottPhotoCo]

Bernice,

Success!

I did exactly as you instructed and it now works smoothly and as well as any other much newer lens I have.

The key was careful disassembly and counting the 26.5 turns it took to remove the control ring. I learned a lot. I had to do this all without glasses as I can't see tiny things with them.

I carefully cleaned the threads and any muck I could retrieve from the slot. Patience is a virtue, that's why I did it over 2 days, so I would not rush.

I used a high grade PTFE Food Grade lube, good for -45F to 450F, which I applied only to the ring in very small amounts and then wiped off the lube, leaving a tiny amount in the ring's thread grooves.

I am very happy with this lens now and will be using it extensively.

Thank you so much Bernice!

This is exactly why I find this board and the members here so valuable. What a great community.

Tim
www.ScottPhoto.co

[Bernice Loui]

Great news and congratulations on the nice results. After doing this for the first time, the next one will be easier. Don't be surprised if all the sticky aperture rings get this same treatment in time as they are SO much nicer to use with a smooth running aperture ring.

Note on lubricants. The earlier Goerz and other lens barrels are made of brass or brass alloy which works great with PTFE based lubricants. Later Kodak lens barrels are made of aluminum alloy and more than a few with brass aperture rings. This was done to prevent aluminum to aluminum galling. On these, use a synthetic base grease with moly like Redline CV-2. This has proven to be good as it is not too thick and has moly to prevent the aluminum from galling.

The later Schneider barrels made of aluminum with a anodized finish should also be lubricated a synthetic moly grease as the galling problem could be more of a problem due to aluminum on aluminum threads. While the anodized finish helps prevent galling and reduced friction, lubrication makes a big difference.

Do not use PTFE grease on aluminum threads as it tends to promote galling and could cause the threaded parts to become really stuck.

Sharing knowledge gained over the years can do much to help others on this rather curious image making journey.


Enjoy that Goerz classic for it will and can produce wonderful images.

:)
Bernice

[Tin Can]

As a former mechanic, I have a large variety of grease, up to and including Nuke grade anti seize.

This lens is nice, the cells only needed slight dusting. I found it in a basement safe in Ohio. The deceased owner must have prized if over all his 100's of other lens just laying around!

Now I shudder to tackle shutters, but I will over time with patience.

Thanks for your further advice on metallurgical compatibility.

Randy Moe

[BrianShaw]

I'm learning a lot. Some of the shortcuts (like i suggested earlier) sometimes work for a quick, albeit often temproary, fix... there is nothing like a job done right! Thanks, especially for the education in lubricants and compatibilities.

[Tin Can]

I just ordered a jar of Redline CV-2. I forgot about this grease. We used it extensively to lube dynamometer bearings and imput shafts, where we had trouble with lube washout with ever leaking seals. These diesel engine dynos cost $30K per rebuild and we used them under continuous duty, but they were designed for intermittent short term usage. We had to remoive this large heavy objects, once every 2 days to keep them working. PITA, especially for a single worker.

Stuff is nasty and sticks to everything... but great lube.