broken aperture blades in nikkor lens

I was just recently given a nikkor 600mm graphic arts lens that the previous owner just had no further use for. the aperture blades in the lens are coated in rust, and are out of the track or whatever mechanism holds them.
it will not open up or stop down any more than the current stuck phase.
the smaller coupled lens seems to have a special pattern in the blades, so I was hoping someone either knew the pattern or could point me to a repair guide.
about half the blades are not connected at both ends, and all are jammed up in the center of the lens.

oh, and there is this little metal lever that seems like it should adjust the aperture, but it just moves freely. I can see it rotating a ring inside the lens, but nothing happens. is it supposed to link to something?

thanks in advance.

actually, one other question-might i just be better off scrapping the current aperture mount and attaching this lens to a shutter?

thanks again.

Just for personal culture, what's a graphic art lens? I searched on Google without success. A working diaphragm is useful for photographic use if the lens doesn't have threads for ND filters (front, or rear). That doesn't mean it couldn't be used successfully, especially with cameras having a large choice of shutter speeds (1/2000, 1/4000 and maybe 1/8000), but you should have the stuck diaphragm removed first.

Adapting to a camera would not only require a machining work but would also require that the image circle projected on the focal plane is large enough.

If this is a telescope for birdwatching it should already have a tripod mount thread and you might find some adapters for various cameras (not only Nikon), that would be probably much less expensive than adapting its mount to a Nikon camera.

it is a Nikon Apo-Nikkor 610mm 1:9 lens, not a telescope or anything.
graphic arts lens is what I was tol, it is on a lensboard that would be used by a graphic arts camera (which I believe is somewhat like a process camera)
given the size of most graphic arts cameras, it should be able to cover 11x14 no problem, and may cover even larger sizes.

Ah, thanks. One day spent without learning anything new is a wasted day.

The lever on the side of an APO Nikkor process lens operates a cover on the side of the lens. You open the lens to insert water-house stops. These were originally supplied with each lens. If you use the water-house stops, you’d leave the adjustable iris wide open for composing and focusing and then insert the stop.

Someone told me that Nikon also supplied thin filters that could be inserted into the same slot as the water-house stops (but not at the same time). These would most likely be separation filters, as these lenses were intended for process cameras used in the lithographer’s process of converting an image into lithography plates.

I’ve seen a set of the APO Nikkor water-house stops, but don’t own a set. I’ve never seen the filters for an APO Nikkor.

I used a 305/9 APO Nikkor as my first 8” x 10” enlarging lens. It performed very well in that role. Process, enlarging, and macro lenses are similar. Each produces a flat field and is optimized to achievie the best image quality at close focusing distances.

I suggest contacting SK Grimes to lean about the practicality and cost of repairing the iris or mounting the lens in a shutter.

It seems that if there was enough moisture inside the lens to rust the diaphragm blades, then it seems likely that the coatings of the exposed glass surfaces would be damaged from fungus or the water vapor.

is there a way to test if the coatings are still there?

I just took one of my 610mm Apo Nikkors partially apart. If you unscrew the rear cell, the aperature mechanism is visible. The aperature blades have a pin on one side which rides in an angled slot. The other side of the blade probably has a hole in it which fits over one of the pins of another blade. The plate with the slots is retained with a spring wire ring which can be popped out with a small screwdriver. The external aperature adjusting ring is held in position with 3 small screws and 1 larger screw which links it to the internal plate. Removing the large screw will allow the internal plate to be removed. You might be able to remove the rust by soaking in Naval Jelly or a similar product. The "Machinery's Handbook" has chemical formulas for colouring steel. Paint would be a definite no. Although a blackened finish is desireable; you could use them as cleaned without too much problem.
The coating on the lens surfaces is a bronze or blue colour depending on the age of the lens and any damage would be really obvious. Even with a damaged coating the lens would still give excellent results
I have taken apart a couple of Apo Tessars and positioning the aperature blades is a frustrating PITA but can be done. Use low tack masking tape on the external side to hold the assembly together when installing.
Have fun. ;<)

As an after thought; you could use waterhouse stops if you cannot fix the aperature ring and blades. I have filter holders which have the same profile as the waterhouse stops and could mail you a tracing.