Durst lens boards... sixtub, setopla, etc.

[zumbido]

I have a Durst M600. The recessed lens board for 50mm lenses is the Sixtub. The recessed board for the M601 is the Setopla. It seems to be about the same diameter as the Sixtub, but I'm not sure if it is precisely; or if there are other gotchas involved here.

Does anyone have personal experience with whether or not the Sixtub and Setopla are interchangeable? I'm interested because the Setopla seems to be easier to get ahold of.

Thanks.

 

[Jerevan]

I can't say whether the Setopla and Sixtub are interchangeable, but my experience is that Durst lensboards from one machine does not automatically fit another. Even if the diameter of the lensboard is the same, the tapering may be different, in which case you may not be able to secure the lensboard well enough.

 

[Bob-D659]

There is a double taper mount that is just a little larger in diameter than the normal single taper, they do not fit the older enlargers. I had one double tapered board and turned it on a lathe so it is a close fit, but the lens is slightly off center.

 

[zumbido]

Ah, thank you very much. I'm leaning towards just making one at this point, the Sixtub in 39mm mount only comes up once in a while and tends to climb to $30 and above... I can make a replacement much cheaper, just a question of whether I can make it to an acceptable precision.

 

[Bob-D659]

Just be careful when cutting the threads or use a threaded nut. The L39 mount is 39mm diameter with 26tpi Whitworth thread form , not 1mm threads! ! !
The bevel is easy to make to the required precision.

 

[zumbido]

Bob, thanks for the heads up. Given the various alternatives, my inclination for fabricating is to get a 39 -> 42 step-up ring (often used for mounting LTM on Zenit) and bond it with an appropriate light-tight sealant in a 42mm cutout rather than cutting the threads or messing with a lock nut or etc. Reasonable?

 

[Bob-D659]

Sounds reasonable, you could get the tub threaded for the 42mm and just tighten it in place. If gluing it in place, a slow cure epoxy would work well, just degrease everything with a solvent first. Or, just use the adapter ring as a nut to hold the lens in place in a 39mm hole.

Edit: Just for your info, two full threads of 39x1mm threads will work without binding on the lens barrel too much, much more than that and the lens will jam in the threads before it is seated.

 

[zumbido]

That might be easier than an inset, eh? 39mm hole with the ring glued in place behind it. Probably simpler to ensure stability that way as well. Good call.