Durst D659 lens mounts

[Larry Bullis]

I have a Durst D659 which came to me (brand new old machine never used) with no lenses and no mounts. I found a disk for mounting the longer focal length, the 105mm. It is the standard 6xx size, with the 39mm thread which will work with my el-Nikkor. However, the mount for the 50mm lens isn't there and I neither know what it looks like nor what it is called. Durst names their various parts with rather cute names beginning with "Du" such as "Dutube", "Dulamp" etc. There must be a "Duxxx" name for this mount.

The 50mm lens that I want to mount in it is an older Componon with the 23mm thread.

If anyone can provide information about this item's identity, or has an extra one which I could purchase, or knows where it can be obtained, I'd really appreciate your help.

Thanks,

Larry Bullis

 

[Bob-D659]

Here are a couple of pics, cast alloy barrel is 71.5mm diameter, 40mm from the knurled edge to the top of the sheet metal bayonet The lens itself is on a floating metal plate so it can be adjusted to be parallel to the neg carrier. It sits about 20mm down from the top of the mount.

The fine knurled ring at the bottom is an extension aperture adjusting ring, it screws into the front of the lens. There are no visible part numbers on any part of it.

 

[Larry Bullis]

Thanks!

So then, I'm going to try to describe what I make of this. Please tell me whether I'm on the right track:

On the enlarger, there is a tube where the 50mm lens fits that has no apparent way of locking anything in at the bottom, so it must lock in bayonet style 'way up inside.

In your pix, here's what I think I'm seeing. There is a plate that locks into the machine (at the top of the mount) by means of three tabs. Then it looks like there is a tube which serves as a mount for the lens at the same time as it serves as a recessed lens board. It attaches to the lock plate by means of three screws (are there springs?) that are used to align the lens to the system's fixed optics. If this is correct, then the lock plate is not itself adjustable, but the tube/lens mount can be adjusted to it. This would mean that the lens tube might be slightly off the perpendicular to the mounting plate but probably not much. True?

Seems reasonable. I'm going to have to order a manual and see whether I can find a name for this thing. So often, we just find lists of part numbers without even an indicator that points to the machine the part fits.

 

[Bob-D659]

Your third paragraph si pretty much correct.

The three chromed screw ends in the picture hold the lens mounting plate to the tub. The thin metal plate with the three tabs is riveted to the tub by the three small rivets spaced between the screws. The metal plate is spring steel and clamps the tub to the enlarger housing, it also has clearance holes for the screws.

There are no springs, but there are three other screws not visible, that are in threaded holes in the lens mounting plate that act as adjustable spacers for the lens board. The chromed screws pass thru holes in the lens mounting plate and go into threaded holes in the tub, you see the ends protruding thru the threaded holes which are just below the thin metal spring plate. They all are reached from the lens side of the mount.

The rectangular "hole" in the first picture is where the light spills thru to illuminate the aperture ring via a red filter.

 

[Larry Bullis]

Your third paragraph si pretty much correct.

The three chromed screw ends in the picture hold the lens mounting plate to the tub. The thin metal plate with the three tabs is riveted to the tub by the three small rivets spaced between the screws. The metal plate is spring steel and clamps the tub to the enlarger housing, it also has clearance holes for the screws.

There are no springs, but there are three other screws not visible, that are in threaded holes in the lens mounting plate that act as adjustable spacers for the lens board. The chromed screws pass thru holes in the lens mounting plate and go into threaded holes in the tub, you see the ends protruding thru the threaded holes which are just below the thin metal spring plate. They all are reached from the lens side of the mount.

The rectangular "hole" in the first picture is where the light spills thru to illuminate the aperture ring via a red filter.

It's a bit more complex than I thought it would be. Leave it to Durst. They were nothing if not ingenious in the most solid of ways. I doubt that it is going to be easy to find one of these. I've sent mail to various places on the hope one might be out there somewhere. Alternatively, I might have to construct something, but I doubt that it would have the alignment feature, at least not as originally designed.

Great description, though.

I have to wonder where the original mount went. Did I just not recognize it, or did they keep it for the lens that may have been in it.

Thanks once more.

L.

 

[Bob-D659]

You are right, it is a rather complex part. I also left out the description of the variable aperture for the window that lights up the aperture scale on the lens via a red filter. There is a section of the inside of the tub that is also painted gloss white to redirect the light onto the backside of the aperture extension ring which is painted bright gloss white to reflect the light back up onto the outside of the lens barrel and aperture markings.

 

[Larry Bullis]

Here are a couple of pics, cast alloy barrel is 71.5mm diameter, 40mm from the knurled edge to the top of the sheet metal bayonet.

Is the diameter inside or out? Top or bottom of the knurled section? I'm presuming that the measurement to the sheet bayonet is to the top of the flat, not the tabs.

The lens itself is on a floating metal plate so it can be adjusted to be parallel to the neg carrier. It sits about 20mm down from the top of the mount.

"...top of the mount" Is this the top of the flat part of the steel plate, also?

There are no springs, but there are three other screws not visible, that are in threaded holes in the lens mounting plate that act as adjustable spacers for the lens board.

Does this mean that the chrome screws go through non-threaded holes in the mounting plate and set the plane of the lens, the other screws not seen in the pictures then act as "locks" to secure the plane by pressing against the upper plane of the tub itself? If this is true, we'd be able to see one of them if the unit were rotated slightly in the picture, right? (I'm just trying to visualize this, no need for another picture). Are these screws very near the chromed screws? If the chrome screws could pass through sort of beefy springs, would this accomplish the same purpose?

I've done a fair amount of hacking on Omegas, but Dursts have always seemed pretty formidable! I'm beginning to think that I might be able to fabricate something that would duplicate the functions of this part, especially if I can find another Durst "tub" that can be modified to substitute for the cast piece. If I need to do this, I will be grateful for some specific measurements. I'm working on that now, drawing lines on your pix. No need to give them to me yet; I have a lot of work to do before they will help me.

Can you give me a rough estimate of how thick the spring steel part is? That's going to be an interesting challenge with the jeweler's saw! Maybe I could use phosphor bronze. It only has to last for the rest of my life. After that, somebody else may care about it, but I won't. I'm sure that it doesn't get a lot of wear anyway.

The rectangular "hole" in the first picture is where the light spills thru to illuminate the aperture ring via a red filter.
....
I also left out the description of the variable aperture for the window that lights up the aperture scale on the lens via a red filter. There is a section of the inside of the tub that is also painted gloss white to redirect the light onto the backside of the aperture extension ring which is painted bright gloss white to reflect the light back up onto the outside of the lens barrel and aperture markings.

This I don't yet understand at all. I appreciate your patience.

This has been EXTREMELY helpful. I think I'm getting a good picture in mind about how this thing works.

 

[Bob-D659]

I can dimension the whole thing for you, helps that I have the tools and a lathe and milling machine as well. I will make another pic or three from the lens side with the aperture ring extension piece removed.

The sheet steel spring plate is 0.5mm thick. You can see the red windw, the small metal knob is the slider to close the window.

 

[Bob-D659]

Tub ID 69.5
Tub OD 71.5 just above lower knurl
Height inc metal plate 35.6

The window is part of the lens assembly, not the lens mount housing.

Bonus info:

A Durst SEIPLA-75 recessed lens mount tub is 70mm in diameter and 33.5mm deep and could be easily modded to hold a 50mm lens in place.
You would just have to make the spring steel retainer plate, and space it with three washers and screws.

 

[Larry Bullis]

Wow, Bob, what a gift! Thanks! I'm going to look for the SEIPLA-75. Seems to me I've seen one around.

L.

 

[Larry Bullis]

It wasn't a SEIPLA-75. I'll keep looking.

So, is the 105 lens simply mounted on a disk? I found one of those and it fits. I had a brief scare when I wondered whether there might be another "tub" I'm missing.

Currently, I haven't got this thing at home and have no darkroom of my own right now. I may take it to school so I can actually be testing and trying things.

 

[Bob-D659]

The seipla75 will mount in the 105mm side as well. The mounting ring on it is the same as the flat disk. You can probably use a seipla75 to mount an 80-85mm lens instead of a 105. It won't work with a Nikkor 75mm.

 

[Larry Bullis]

So do I need 2 Seiplas then, one for each lens? Does the 105 mount in a tub, or is it supposed to be on the flat disk normally?

I have a good 105, and I can use something else for 2-14 square, or, of course, project on the floor if it needs to be big. I'm no stranger to that! Also, I have another enlarger or two. I have to keep at least the Omega D3, because I have lots of 4x5 negatives. It's easy to set it up for 6x6 or 6x7. I expect the D659 to be the solid center of the darkroom, though. I'm shooting mainly 35mm and 6x9cm now. I'm happy to note that the 659 will accept 70mm; still have a bunch of that.

 

[Bob-D659]

Nope, use a flat plate for the 105. You would need a second one for an 80-85 tho. And to add to the confusion, if you want to make small prints from 6x9 negs, there is a DUTUB which is a lens extension tube so you can make approx 2x3" prints from 6x9 negatives.

For 35mm to 6x9 black and white, the 659 is a dream if its cleaned and working properly. Pretty sure 16x20 is doable on the baseboard from 35mm, hang on a sec, I'll go check........... Ok, the magnification scales on the sides of the head, show 6x on the 105, and 15.5 for the 50mm when the head hits the ceiling, which is before the head is at the top of the column. Max is 6.5x and 16.5x according to the scales, you can read the max numbers when you move the head way down.

 

[Larry Bullis]

Tub ID 69.5
Tub OD 71.5 just above lower knurl
Height inc metal plate 35.6

The window is part of the lens assembly, not the lens mount housing.

Bonus info:

A Durst SEIPLA-75 recessed lens mount tub is 70mm in diameter and 33.5mm deep and could be easily modded to hold a 50mm lens in place.
You would just have to make the spring steel retainer plate, and space it with three washers and screws.

Here's a new development.

Seipla 7539 is on its way from Latvia. Who knows how long that's going to take.

When my stepfather left the earth, I wound up with his 50/f4 componon, just like the one in the pictures you posted. It is in the tub used in the Durst 606. The OD of that tub, just above the mounting ring, is just right at about 68.3 +or- 1 or 2 in the second decimal place. Seems to me that it would fit neatly into the Seipla 75. The top of the tub casting is about 23.75mm above the edge of the mounting ring. This is hard to measure accurately, and anyway, the inside of the tub to the mounting ring would be the important thing to know, so I'll figure out how to measure that.

Since I don't have the Seipla tub yet, I can't be sure I'm visualizing this correctly, but it seems to me that I might get lucky. For one thing, your pictures show the lens suspended down in the tub, at some depth. I'm wondering whether that depth might miraculously correspond close enough to where the lens would be with the 606 tub mounted in the seipla. I also suspect that the 39mm hole in the seipla would be big enough to give the lens full view of the 35mm negative. It might also be functional as a lens shade as a bonus, not that it is necessarily going to be needed for that, but as long as the whole negative is unobstructed to the lens, it wouldn't hurt. If need be, I could enlarge that hole.

If this would work, it would be incredibly easy. I wouldn't have the neat three point screw adjustment, but it doesn't seem that would be likely to need adjusting anyway. I could pierce the 606 tub and fit a red filter to it for f/stop illumination, but that isn't even very important -- I've actually memorized the f/numbers, and I can count.

What do you think? Will that work?

 

[Bob-D659]

Hmmmm. I haven't seen a Durst 606 in person for decades. The Dust 39mm mount the Componon lens is mounted in has the rear element a ways down from the 39mm thread. The top of the 39mm thread in the special D659 tub is almost at the exact same height as the Seipla 75. The tub is bored out larger and the adjustable plate is almost a mini tub or recessed lens board with the 39mm thread recessed up into the larger mounting tub. Kind of hard to describe first thing in the mornimg.

It would need some way to adjust it as that's how you adjust the lens height to match the auto-focus cam.

 

[Larry Bullis]

... Kind of hard to describe first thing in the mornimg.

It would need some way to adjust it as that's how you adjust the lens height to match the auto-focus cam.

Well, you have plenty of time for coffee or whatever is necessary. I have no idea how long it takes a package to arrive from Latvia, but I doubt it's going to get here real soon.

My Componon is the earlier version with the 25(?)mm thread. Isn't yours also? It looks the same in the picture, and yours appears to have an even earlier serial number than mine. We bought two of these lenses in the mid '60's, as I recall. They are very cute, actually.

Looks like I'd have to get pretty darned lucky for it to work the way I was hoping it could. It seems to me, though, that it's going to depend upon just how far down from the 39mm thread in the Seipla the lens has to be. If not far enough, it won't work. Whether I use the 606 mount or a movable plate, that will be the issue, seems to me. I believe that I have the nut for the lens threads, so there would be no problem mounting the lens in a plate.

Since the adjustment is needed, the plate may be a better plan, because the 606 tub is a single casting. Using the tub is still an attractive idea. Seems to me the alignment would be easy. It might still work if the lens needs to be down aways; I suppose I could use set screws to lock it in.

 

[Larry Bullis]

Looking at the pictures again, and considering that you say that the adjustable plate is like a tub, it seems to me it may well work to use the 606 tub. If my assessment of the dimensions is correct, the smaller tub will fit inside the seipla with close, but not overly tight tolerance. That would (the big IF) permit some slight adjustment of the mounting plane to tune the axis as well as allow a fairly wide range for focus.

 

[Bob-D659]

I believe it is a 25mm thread, I didn't measure it when I had it out of that chromed mount. The back edge of the rear lens cell is recessed approx 13mm down from what would be the topside of the seipla lens tub.

 

[Larry Bullis]

I'm guessing that it just might work. It looks like there will be about 5mm to spare, which would give adequate room to move.

Do you have a recommendation for material to make the mounting ring/tabs out of? Spring steel would be too hard to work with the tools I have. How about phosphor bronze?

 

[Bob-D659]

You could probably use a dead cd blank. If you look up into the bore you will see the three lugs the clips sit on top of. There is enough clearance for a thickish piece of something above them. You aren't supporting much weight, and all the clips do is hold the lens mount snugged up to the bottom of the lugs. You could even use three pan head screws, with the threaded end slotted so you could tighten them from below after twisting the lens tub in place.