Mounting 80mm EL Nikkor

[graywolf]

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.

 

[tkamiya]

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.

 

[Mike Wilde]

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

 

[graywolf]

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.

Is that flange held onto the disk with screws or rivets? In other words could it be removed and put on my B22 lensboard?

 

[Ian C]

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.

 

[graywolf]

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?

 

[David Brown]

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.

 

[Bob-D659]

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.

 

[Reinhold]

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.

Reinhold

www.classicBWphoto.com

 

[graywolf]

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.

 

[Ian C]

Exorbitant Price for a Used Lens Board?

I examined my old version 75/4 EL Nikkor and found that the threaded shank is 4mm in length. This is a lens of the same era as the 80mm El Nikkor you have and probably has the same shank dimensions. Due to the chamfer on the end, the last thread terminates about 3-3.2mm from the shoulder.

That’s about the same as 1/8 inch, so you must have a very thin board or use a threaded mount.

Beseler counterbores its lens boards so that the metal is thin enough to accommodate most, but not all 39mm lenses as in this photo.

http://www.bhphotovideo.com/c/product/4515-REG/Beseler_8021_39mm_Flat_Lensboard.html

But for really short shank lenses, Beseler owners might have to use a board with a threaded flange like this one

http://www.bhphotovideo.com/c/product/111891-REG/Beseler_8086_39mm_Lensboard_with_Mounted.html

Although Omega-Brandess no longer supplies the 421-020 39mm board with the 39mm threaded flange for the B22/B66, it still offers the 421-056 for the D5/D6.

http://www.bhphotovideo.com/c/product/39490-REG/Omega_421056_Flat_Lens_Plate_with.html

The current price for the D5 board is likely what you’d have to pay for a new B22/B66 threaded mount at 2011 prices if it was still made.

So, paying $30 to get a used one, while annoying, is still something of a bargain. It all depends on how you look at it.

 

[Reinhold]

Another backwoods possibility that I've done out of necessity:

39 mm is 1.535 inches, (1/32" larger than 1-1/2").
With an ordinary holesaw, bore a 1-1/2 inch hole in a piece of 1/4" Masonite.
Then sand or file it a tad larger.
This will let you thread the lens directly into the relatively soft wood fibers.
It will be plenty secure.
Make sure it's in straight and flat to the threads seat.
Trim the piece to size and finish it as it suits you.

Then super glue that "threaded adapter" onto the face of your existing board.

Reinhold

 

[graywolf]

But, to my way of thinking, I can get a later model lens for that $30 or a little more, and use my existing lens board. In fact I have a friend who is going to look and see if he still has his enlarging lenses, and if so give them to me. A new enlarging lens is several hundred bucks from B&H, does that mean I should be happy paying $150 for one?

I just missed out on a free enlarger and jobo processor because I did not get back to the lady quick enough, used darkroom equipment is cheap unless you are buying it from a dealer. You can pay $20 for a retaining ring on eBay, or order it new from B&H for $6.85 with free shipping. It is all a matter of common sense. Since I live off SS, and have neither a healthy bank account, nor a credit card, low cost is a necessity for me. $30 is a dozen rolls of film, it is my eating out budget for 3 months. I am not just being cheap.

I do thank you, Ian, for pointing me to the seller. Their price is fine, it is the $20 shipping for something that will fit in an envelope that bothers me.

 

[graywolf]

Just not to leave this thread hanging. I finally bit the bullet and bought the proper threaded lens board.