Durst L1840 Enlarger 8x10 10x10--Everything you wanted to know...

[Thodoris Tzalavras]

From the durst 2506 documentation.

Gary,

Thanks for sharing the 2506 instructions for installation on the rails.
The text does provide some information on proper procedure for putting the rails on the floor.

However, the L184 base has different wheels.
Here is a picture that I took for my records, before assembling the upper column:



For reference, on the left is a brochure for the 2501, and on the right for the L184:



By the way, since the 2506 has the same (or close enough) light source as the CLS2000 head, if you have any manuals (user and repair) that you can share, I would really appreciate it!

[Thodoris Tzalavras]

You DON'T want any rubber under the rails. That will induce vibration. You want as solid, flat, and firm a floor as possible.

Drew,

Can you elaborate on this, or provide sources?
I'm not saying you're wrong, but my thought on putting rubber under the rails was based on two different sources.

1) This is an excerpt from Lefkowitz's "The manual of close-up photography":



2) Celestron sells what they call "vibration suppression pads", to put under the feet of your tripod.

In general, I prefer to do my own testing.
Trying both options (with and without rubber substrate under the rails) and comparing actual prints side by side would be my preference, but in this case I will have to make a choice up front and stick with it, or risk hernia…

[Drew Wiley]

My gosh! A massive L184 and rail setup is nothing like that tiny macro illustration or a tripod based Celestron, which also sounds hokey. I've seen astro and pro wildlife photographers at work many times, and there was even a Celestron dealer right down the street, and they never used rubber pads or ordinary tripods! Hard (not soft) rubber cups and pads are just for sake of preventing floor scratching from tripod feet. I also sold surveying instruments and survey lasers requiring precise alignment. You don't want any kind of soft rubber under under such things - it amplifies vibrations.

And yes, I do know what I'm talking about. I interacted with major photo, tech, and even aerospace labs as a supplier of materials. The company I worked for even had massive steel rail and sheeve systems in stock that would support tons of load. I don't know specific sources in Europe, but you can at least go to the well-illustrated McMaster Carr website in this country and study that particular category of INDUSTRIAL items, and learn about what is available. Photo gear suppliers are not the right kind of source for this kind of thing.

You don't want vibration period, or anything bouncy. The floor needs to be rock solid. Bridge any unevenness with a firm new flooring over
the area to be used, not with rubber shims. The rails need to be completely level, flat and straight, bolted firmly down. I'd even recommend a third overhead steel beam trolley supporting the head from above, though that might not be feasible in some spaces, or too complicated a project for you personally.

[Kiwi7475]

Rubber cannot amplify vibrations unless you make it resonate at its natural resonant frequency, like any other material. that’s just physics. But rubber is one of the best vibration dampers out there because it can be made to have a high damping coefficient. The only concern for rubber is if you’re hitting whatever it supports with your body or feet or whatever.

[Thodoris Tzalavras]

Drew and Kiwi7475,
Thank you both for your contributions.

[gary mulder]

Gary,

Thanks for sharing the 2506 instructions for installation on the rails.

By the way, since the 2506 has the same (or close enough) light source as the CLS2000 head, if you have any manuals (user and repair) that you can share, I would really appreciate it!

The light source of a 2506 is a electronically controlled closed loop light source with filters controlled by stepping motors. That is a very different beast.

Do you have a closeup photo of the rear wheels of the l184 ? A T rail will always have some slack. Hard to achieve enough precision. I have worked with 5 horizontal Durst but never on a T rail. Look closely at the photos ic-racer posted. The front rail is a flat rail.

[Tin Can]

I may be not seeing correctly

Is one floor rail captive and the other allows wander

Just watching

[Drew Wiley]

Kiwi - have you actually installed or worked with a big horizontal enlarger? And a horizontally-oriented L184 chassis is even worse, because it's a big post. There is simply no substitute for a truly flat stable floor. If that involves seeking help from a construction professional to reinforce and level the floor, so be it. I taught classes on such techniques; and we shipped cargo container loads of self-leveling cement to military installations and defense contractors all through the Pacific, as well as to all kinds of local industries and R&D facilities, including major photo labs. It really isn't all that expensive to do it right unless there is a major floor flexing issue to begin with. No need for rubber. And most rubber shim doesn't last all that long to begin with, unless it's pure silicone.

There is no flat rail, but an illustration of the option of either L and T-style rails. I'd rather both of them be T-style for sake of greater rigidity and ease of mounting. All four sheaves are identical.

[Thodoris Tzalavras]

The light source of a 2506 is a electronically controlled closed loop light source with filters controlled by stepping motors. That is a very different beast.

Do you have a closeup photo of the rear wheels of the l184 ? A T rail will always have some slack. Hard to achieve enough precision.

I based my comment on information provided by Durst-USA.
This is an excerpt from a pdf:



Also, all four wheels are the same.

[ic-racer]

I have never seen a picture of a HL2500. May be a rare beast.