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Thread: Need help figuring out how to build a roller base for a Jobo 3005

  1. #1
    Gonzo Photographer
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    Need help figuring out how to build a roller base for a Jobo 3005

    Nobody likes long postings so in keeping this short I’m needing some help building a motor base for a large Jobo film processing drum. Details are in the second posting below.

    I have some ideas in mind and a rough design. A professional machinist I was working with and who was going to build this has been blowing me off time and time again for nine months, so I am at my wits end and I’ve finally realized I will just have to build it myself.

    Are there any mechanical and electronics savvy professionals out there who could help me with some component selections? I’d be happy to pay for your time to look over things and help me refine a design. Please PM me or post here.
    Last edited by konakoa; 13-Nov-2017 at 22:35. Reason: typo

  2. #2
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    Re: Mechanics and Electronics Professionals, Please Help with Jobo Drum

    The details:

    What I’m after is a oversized yet portable and extremely quiet motor base for my Jobo drums. I want to emphasize the quiet part. I’m surrounded by vibrating and otherwise noisy objects and I don’t want this motor base to be another one.

    Before it’s mentioned, please, I do not want to buy an old Beseler motor base. I’ve already done that. It’s too narrow for the drum and the drum also walks off the motor. Similarly, I do not want to buy a huge Jobo CPP/CPA processor as I have no need at all for the temperature control (I’m processing black and white film) and no room to store one of these machines.

    I’ve been borrowing heavily from the ideas on this webpage as this design is ideal: http://colinflanarygraham.com/darkshop/?p=2249

    The motor base I want to build needs to be a bit bigger to handle a Jobo 3005 drum about 14” long, 8” in diameter. The weight of the 3005 drum with chemistry is about six to seven pounds by my estimate. I need the motor to be reversible with a speed control. It need not be programmable. A simple mechanical forward and reverse switch and knob for the speed would be preferable.

    When it comes to electronics I know just enough to realize I know nothing. I could use really use some help understanding what kind of torque I should be looking for and what kind of voltage I should be looking at. As the motor will be running for about twenty minutes per film run the duty cycle could be important so the motor doesn’t get hot.

    On the mechanics side, I’m looking at a multitude of bearings, rollers and drive pulleys and some pointers would be really useful.

    Again, please PM or post here if you can help!
    Last edited by konakoa; 13-Nov-2017 at 19:50. Reason: Clarification

  3. #3
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Lightbulb Re: Mechanics and Electronics Professionals, Please Help with Jobo Drum

    Quote Originally Posted by konakoa View Post
    On the mechanics side, Iím looking at a multitude of bearings, rollers and drive pulleys and some pointers would be really useful.
    All of the mechanical stuff you would ever need is at McMaster-Carr Supply Co:
    http://www.mcmaster.com

    They've been in business over 100 years, and carry everything.

    You want to use a DC motor, not AC.
    AC motor speed can be adjusted but it requires special circuitry.

    DC motor speed is adjusted just by changing the applied voltage.
    That's why railroad engines use DC motors rather than AC.

    The support wants to have three feet, not four.
    Two are on one side of the tank and one on the other side.

    One of the feet on the two-side should be adjustable in height.
    That lets you adjust the support perfectly level so the tank won't walk.

    - Leigh
    If you believe you can, or you believe you can't... you're right.

  4. #4
    Small town, South Carolina, US
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    Re: Need help figuring out how to build a roller base for a Jobo 3005

    I use a Uni-color or Beseler base for the large end and a separate set of idler rollers at the neck. I added a third idler roller wheel perpendicular to the cap end to hold it in place. Or you could put one on each end to hold the tank in place. Works fine but my tank is smaller than yours.

  5. #5

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    Re: Need help figuring out how to build a roller base for a Jobo 3005

    DC motor speed is better controlled with a PWM controller - constant voltage, variable on-periods - which provides better torque, and thus control, at low speeds. Controllers for 12 and 24v motors are all over the bay, and are inexpensive - a few pounds/dollars. I'm *guessing* here, but a suitable motor to turn, say, a kilo of tank and chemistry would probably need no more than a watt or so; there will likely be a mechanical advantage with the drive system. Belts are significantly quieter than gears. Making sure you have no hard coupling to resonant surfaces - the case of the unit, the work top - will keep things quieter. Rubber feet and mounts are your friend.

    Neil

  6. #6
    Randy Moe's Avatar
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    Re: Need help figuring out how to build a roller base for a Jobo 3005

    Something to think about.

    Quiet rock tumblers.

    https://rocktumbler.com/tips/how-muc...-tumbler-make/

  7. #7
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    Re: Need help figuring out how to build a roller base for a Jobo 3005

    The drums kept walking off my Beseler base and it ran a little slow so that was no good. I'm actually using that exact rock tumbler as a motor base now Randy. I had to swap out a set plastic rollers it came with on one side as the rollers really banged and ratted around, but works very well with a smaller Jobo 3006 drum. It runs nice and quiet now. Been using it for two years. The rock tumbler is meant for heavy loads going 24/7 for months so the motor is strong. The problem is it's the biggest model they make. No way the 3005 Jobo will fit on it.

    So it looks like I definitely need a brushed DC motor on the base I want to build. 12 volt is very common. I see 24 volt too.

    Click image for larger version. 

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  8. #8
    Randy Moe's Avatar
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    Re: Need help figuring out how to build a roller base for a Jobo 3005

    Your projects are always very nice.

    Your next iteration may even get me rolling.

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