Mounting 80mm EL Nikkor
Hi, I just bought an older, chrome base, 80/5.6 EL Nikkor to use on my Omega B22 Enlarger. However, when I try to mount it on the lensboard, the retaining ring will not start on the threads.
The ring goes on off the board, it works fine with my 50/2.8 EL Nikkor, so it seems to be a problem with the length of the threads on the 80.
Has anyone any suggestions? I could try to find a threaded lensboard, but it would probably be cheaper to buy an different lens.
I have a threaded lensboard that is designed to go on lens cone of Omega D-2 and D-II series. The thread part is a small flange looking thing with inner threads. (39mm). Then, there is a small disk that bolts to the lens cone. If that'll be any help to you, I can part with them. If interested, please PM me.
Develop, stop, fix.... wait.... where's my film?
DIY- coat the thread of the lens with vaseline, and smear to a thin layer.
Place lens in lens board, and wrap with a piece of string coated with still hot hot melt glue. Use laundry gloves to keep the glue off your skin, and partially insulate them from the heat
Alternately, use Fimo modelling clay rolled into a ring, and pack it against the threads and leave for a doy or so. Can be overcoated with hot melt glue to reinforce.
Cover lens and paint the affair black, or blacken with a black 'sharpie' permanent marker
my real name, imagine that.
Is that flange held onto the disk with screws or rivets? In other words could it be removed and put on my B22 lensboard?
Originally Posted by tkamiya
The DII lensboard is much larger in diameter than the B22/B66 board and is held to the plate or cone via two screws.
It doesn’t have the two bayonet slots of the B22/B66 board and the screw holes are considerably farther apart.
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Ian PM'd me with a place that had a couple of the proper lensboards in stock for a reasonable price. I inquired by email, and they called me back on the phone. The price was right, but $20 shipping was not. Isn't it insane, you can get the lens rather cheaply, but they want a fortune for the piece you need to mount it. In this case the lensboard would have come out to the same as I paid for the lens.
I am beginning to think that what I may have to do is take some JB Weld epoxy and glue the ring to the outside of the lensboard I already have. Anyone see a reason why that should not work?
Years (decades) ago I made a threaded lensboard for my Chromega B (same as B22) by attaching a retaining ring to the board with small screws. I see no reason why carefully applied epoxy would not work.
Sounds like that lens board is quite thick, what is it made of? You could file a shallow taper towards the hole, thinning the metal to expose another thread on the lens, it's not too difficult, and the front surface is the registration plane for the lens.
As Bob says, the board is probably too thick.
I have seen some that have a counterbore on the backside which makes the effective thickness about 1/16".
Depending on your tooling, there are a couple of ways to counterbore a lensboard.
With a drill press and a hole saw it can be done if you clamp the board down ...firmly...
Find a retired home shop machinist. Using a 4-jaw chuck, he'll whittle that board down in a few minutes.
Using a Dremel grinder to reduce the thickness would be a hassle, but it's possible.
Another way is to mount the lens on a piece of 1/16" thick aluminum, which is then bonded (or screwed) onto the face of your existing board. Some spacers between the original board and the new mount will provide some clearance for the retaining ring. I think this is probably the way I would go if I didn't have good tooling.
Bob is correct, the lens must be mounted so that it's axis is exactly 90° to the face of the board.
Soooo... if you use JB Weld, make certain that the ring is not "cocked" on the board.
I don't know that the lensboard is all that thick. It looks like 1/8 aluminum. I live in a small, not technically orientated town. The only machine shop quotes $90 for the simplest job. When I lived in a big city up north I knew folks who would do such things just for the fun of it. The thing of it is that you can get enlarging lenses for next to nothing these days, it hardly makes it worthwhile spending a lot of money to mount a $30 lens. I do have another unthreaded lensboard on the way (just so I would not have to switch the lenses back and forth), maybe it will be thinner, but I doubt it.