Zeiss Ikon Nettar lens clean and re-assembly

[Skiver101]

Removed this from front standard and dis-assembled as far as I could dare.
With some fiddling and twiddling, I finally got access to all lens surfaces and successfully cleaned elements of minor fungal growths; I took a gamble and lubricated the shutter mechanism with white spirit - dribbled sparingly into all available apertures that presented themselves (it seems to have worked a treat, the timer now works great and the shutter is a lot slicker than it was -time will tell ).

As I cannot see the focus through the viewfinder; My question is:
Has anyone experience of this re-assembly, and what is the procedure for connecting these two elements back together in order to ensure the focus of the lens is aligned with the scale ?
I don't want to risk several rolls of film trying to guess.

sorry about the quality of the uploads...

JP

 

[rubbernglue]

I have made such a cla like 6 month ago and I made it wrong and learned later what it was, unfortunately Ibhade a travel-roll in between which was very much fuzzy...

The lens on mine could easely be screwed out if just unscrewing a small peg-screw which ended somewhere at infinity focus I think. Then I folded the camera and opened the back in order to reach the rear ring-screw with a special tool in order to get all glass out of the way. I then drenched the shutter and apertureblades in electronics-spray, which vaporates in a minute or so. The very not so good thing I did then was at re-assembly, when I simply just screwed on all optics again. The thing was that (at least the front element screw) could hinge 180° apart, and I hade hinged the wrong of these, making my images fuzzy of course. To properly see if you have focus at a set distance, take a ex. failed roll of film and mount it thoroughly between the spools and use a loupe on the film to see if you have proper focus. The focus will be far off if the lens is mounted wrong.

 

[Skiver101]

''To properly see if you have focus at a set distance, take a ex. failed roll of film and mount it thoroughly between the spools and use a loupe on the film to see if you have proper focus. The focus will be far off if the lens is mounted wrong.''

That sounds good - I never thought of applying a focus screen.
Thanks rubbernglue

 

[shutterfinger]

I took a gamble and lubricated the shutter mechanism with white spirit - dribbled sparingly into all available apertures that presented themselves (it seems to have worked a treat, the timer now works great and the shutter is a lot slicker than it was -time will tell ).

Go to ebay and search for Ultrasonic Cleaner then select the jewelry cleaning option to get the machines suited to shutter cleaning. One that has a 3 to 5 minute, usually stated in seconds, cleaning cycle and 1 pint (.47 liter) cleaner capacity is adequate. Use 90% isopropyl alcohol as the cleaner.
Referring to your first picture the screw opposite the f22 mark on the right is the retainer ring lock screw. Mark that slot, remove the screw then unscrew the center retaining ring counting the number of turns it takes to remove the ring.
The shutter face plate and speed ring will now lift off the shutter. Set the shutter to T or B before lifting the speed ring off and note its position relative to the shutter case pc socket or cocking lever. Do not attempt to cock the shutter with the speed ring/face plate off. Take a good picture to identify the parts positions. Set the aperture to f22. Place the shutter open side down in the ultrasonic cleaner, fill with the alcohol. Run 3 to 5 cleaning cycles allowing it to rest 5 minutes between cycles. Cleaning cycles in close succession will cause the alcohol to get hot. Hot alcohol will cause paint to peel off where finger oils have penetrated it.

Take the shutter out of the cleaner and allow to air dry. A drop of clock oil or similar about the size of a straight pin point can be applied to pivots if desired. Reassemble using the retainer ring number of turns recorded during disassembly and reinstall the lock screw. This is 100% better than flushing with lighter fluid or solvent and about 75% of a complete tear down, clean, reassembly.

Dirt and dissolved lubricant will settle to the bottom of the ultrasonic cleaner as a dark gray to black fine sludge and may discolor the alcohol.

 

[Andrew K]

use a piece of "Scotch magic Tape" as a ground glass - it's a frosted sticky tape you can photocopy through (there are other brands).

Stick a piece from film rail to film rail (the parts next to the opening where the film runs through), and make sure the tape is tight - I run mine from top to bottom on a Zeiss folder.

Then set the shutter to B and lock the shutter open (cable release). Screw the lens unit in and focus the lens until infinity looks sharp on your ground glass (tape) - if you need to relubricate the helicoid use a tiny amount of fishing reel grease on the lens unit when screwing it in.

Now refit the focus scale to the lens group, and make sure the focus scale it is set to infinity. Now check the focus on the ground glass (sticky tape) and check to make sure nothing has moved and you're still in focus. If nothing has moved tighten the 3 locking screws. If it has readjust focus to infinity, reset the focus scale and check again. Once it's focussed to infinity with the focus scale set to infinity tighten the locking screws.

I've fixed over 50 folding cameras over the years and it works every time

 

[Skiver101]

shutterfinger - That is a great and comprehensive reply. I'm sure I will reference this thread in future forays. Thank you very much.
Unfortunately, I did try to remove the front plate in order to access fully the front lens cell to clean the edge areas, but found said screw (at f/22 mark) has been threaded; by a previous tinkerer no doubt, so access was denied me. I just cleaned as best as I could manage.
p.s. The white spirit has taken nearly 24 hours to approach complete evaporation - I must source proper lubricant.

Andrew K - Thank you for that great walk-through. Much appreciated.
I have already screwed the front on; first all the way to the face, then screwed forward until the first appearance of the stopping-pin hole at the marker-arm. I'm still doubting, but the action and separation distance looks and feels very familiar. I will proceed at that, and try to source the Scotch tape that you mentioned - I'm not sure how it is branded in Scotland, ironically, but I will no doubt accquire something useable whatever. If things are not right, I will back-up and follow your reply step by step.

Thanks again guys, it's appreciated.

p.s. If I may be so bold; as to ask which orientation for replacement of rear lens cell - it is flat on one side and convex on the other - I'm not sure which side should face the film-plane and which side should face the shutter diaphram ?

JP

 

[shutterfinger]

That screw may be retained by thread locker. The type used in standard camera work will dissolve with fingernail polish remover/acetone.

I may have overlooked you mentioning what lens is in your Nettar as according to Camerapedia there were several.
Its likely a basic tessar and the convex side faces the rear of the camera (film).

 

[Skiver101]

That screw may be retained by thread locker. The type used in standard camera work will dissolve with fingernail polish remover/acetone.

I may have overlooked you mentioning what lens is in your Nettar as according to Camerapedia there were several.
Its likely a basic tessar and the convex side faces the rear of the camera (film).

The ''thread locker'' that you mention is a new one on me, (and I'm imagining that this will render the screw tight ?). However, this screw just spins and I can't seem to get enough purchase on it with tweezers to withdraw it. But this access is not critical as the shutter seems to be operating a lot smoother as is. I think I'll leave well alone for now, I'm just not confident enough - I have about 7 or 8 rolls of film left; and if I go too far and mess up I'll have no medium format camera to put them through.
I have a strong suspicion that the lens is of the basic type as you say - there are three elements as far as I can tell. I will mount the rear element convex side facing the film plane and hope that I get lucky first time.
The white spirit has now evaporated fully, and I can put everything back together and try to zero the focus.

It's actually all great fun ...honest

 

[AgX]

I took a gamble and lubricated the shutter mechanism with white spirit - dribbled sparingly into all available apertures that presented themselves (it seems to have worked a treat, the timer now works great and the shutter is a lot slicker than it was -time will tell ).

Do you mean "cleaned" or actually "lubricated"?

Translating technical terms between languages can be difficult, but to my understanding "white spirit" refers to a solvent that evaporates quickly without residue.
Thus it only could be used for lubrification, if some oil already was at parts of the shutter and now got re-located, that is: spread al over.

 

[shutterfinger]

Do you mean "cleaned" or actually "lubricated"?

I think he is referring to flushing it with solvent as in Naphtha or camp stove fuel that is mostly naphtha.

However, this screw just spins and I can't seem to get enough purchase on it with tweezers to withdraw it

That should be Pressure. What language are you translating from?
The screw is likely stripped as it would come out if it were good or a smaller size.
Apply upward pressure on the base of the screw head while turning it counterclockwise or cut the screw head off.

The lens is 4 elements in 3 groups. The rear is a cemented pair. Light travels the direction of the arrow.

 

[Skiver101]

As shutterfinger states, I mean an 'uneducated' and crude, but minor and targeted flush; through any gaps that were available at the stage shown in uploaded images. I'm just trying to better a shutter release action that was failing/sticking once or twice during every roll. I couldn't identify the specific, so I went for the flush.
I don't know the 'technical' name for white spirit, but I'm sure a simple google search would illuminate.

PARLIAMO GLASGOW

Thanks for that little diagram shutterfinger - the cemented pair looks similar to the rear element I asked about.

JP