Motorized BTZS tube spinner

[AJ Edmondson]

With the Hurst high-torque motors a pause or "interrupt" causes them to reverse. These are (or were) available in various rpm versions but the speed was a function of the gearbox and thus not variable. To give you an idea of what Hurst meant by "high-torque" I bought two, one for the BZTS tubes and a second to drive the front standard of an Elwood 8x10 Enlarger. If you have ever seen one of these beasts you know that the bellows, standard, lens-board and lens add up to a significant amount of mass and the Hurst motors are still going strong after twenty years or so!

[salihonba]

I made it about 6 years ago, in plastic gears and a small motor,

But I want it stay in the tub, so a smaller type was developed,

very good for individual tube time control
I wrote to Phil Davis about this type, he said he would rather keep things simple........
Since I found that negative presented well with no reverse rolling, so I did not try to reverse during the developing...

[Daniel Stone]

that's pretty nifty!

-Dan

[jeroldharter]

That looks great and simple!

• Could you not put the larger one in a bigger tray?
• Do you have a problem with the tubes floating up off the gears if used with a water tempering bath?
• How do you deal with the gears attached to the tubes making them "tippy" when upright?
• Could you do that for 8x10 tubes (3)?
• If so, what would you charge for these?

[Dave Jeffery]

"With the Hurst high-torque motors a pause or "interrupt" causes them to reverse."

I'll look into those as I think I've decided to build a hot dog tube processor that will spin one or two Jobo drums as well. No sense using seperate tubes for the same development times so a combination of drums and tubes would be best. I looked at the Hurst motors and really like the quality so thanks for the heads up as that is probably what I will use now.

Is there a cheap timer and relay that can be used to interrupt the curcuit? The Arduino controller is probably over kill if this interrupt feature is still built into the motor's controller.

Thanks Joel
--------------------------------

Nice processor Salihonba! I will probably use pulleys and belts since they are so cheap and I don't have to be exact on the hole spacing as I'll be using a hand drill to make this. Spinning a couple of drums will probably require a beefier system as well.

------------------

Jerold,

Now that I have decided to make the processor stronger there is no reason it couldn't be made wider and spin 8x10 tubes. A unit could be made that is adjustable and could process 4x5, 5x7, 8x10 tubes and / or drums of the same length. Unfortunatley this is not something that I will be able to make quickly. A decent craftsman should be able to look at this information or Salihonbas and be able to make one for you. Lots of parts on the Robot Shop website.
If you need I could do some simple sketches and post them. The exact design of the spring loaded tube release has not been finished yet. I may switch to letting gravity hold the tubes in place.

One could imagine that universal end caps could be created that could be epoxy fiberglassed onto any length of tube or drum. If this were to become a product standard 2 and 4 roller spinning ends could be made and people could just order how may roller ends they would like and add more capacity as needed. Various belt lengths and some length adjustment space at the motor base would make a somewhat universal design possible. Just adjust the width of the unit for different film sizes.


I aslo like the idea of making a drum that has a chemical resistant big plastic ball valve with a removeable custom handle to drain it. One would just slide a flat flange on the drum into a receptacle that would make a light tight connection and just open the ball valve to drain the drum quickly. Obviously the tank that catches the developer would have to be light tight as well but large schedule 40 pipe would work. Shut the ball valve and flip the drum, valve upright, into a similar light trap for the top of the drum to add the stop bath. Once the drums were loaded in the dark everything else would be possible in daylight.

What other features would be nice to have?

Thanks all!!!!

[salihonba]

That looks great and simple!

• Could you not put the larger one in a bigger tray?
  
  Yes I did, and it worked fine
• Do you have a problem with the tubes floating up off the gears if used with a water tempering bath?
  Carefully control water level in tub then it makes no problem
• How do you deal with the gears attached to the tubes making them "tippy" when upright?
  oh, I made a pile of bigger tubes for resting.
• Could you do that for 8x10 tubes (3)?
  donno, never try that, I shoot 4x5
• If so, what would you charge for these?
  try do that yourself, it is quite easy, and I should try rubber belt for new version.

[younghoon Kil]

I made it about 6 years ago, in plastic gears and a small motor,

But I want it stay in the tub, so a smaller type was developed,

very good for individual tube time control
I wrote to Phil Davis about this type, he said he would rather keep things simple........
Since I found that negative presented well with no reverse rolling, so I did not try to reverse during the developing...

This may be late, but could you tell me what materials were used to make these tubes? I want to make it too.

[Roger Thoms]

This may be late, but could you tell me what materials were used to make these tubes? I want to make it too.

Those tubes are manufactured and sold through “The View Camera Store”, although they show out of stock right now. Here a link to a thread on 5x8 development, see post #9 for an example of 5x7 tubes I made from electrical pvc and AB’s plumbing fittings. You can make tubes for 4x5 the same way. https://www.largeformatphotography.i...=1#post1032416

Roger

[bmikiten]

The whole point of the water bath was to provide not only some modicum of temperature control but also the random motion that allows for the even development. When Phil and I were developing the BTZS tubes, the entire point was to NOT do what Jobo was doing and to avoid motorizing it. Just an FYI.

[Roger Thoms]

Good point on the water bath, that’s how I’ve always used the BTZS tubes. It’s really hard to beat the water bath for even development.

Roger