DIY manual turntable - questions

Reptilian Feline Aug 13, 2020

  1. Reptilian Feline

    Reptilian Feline TrainBoard Member

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    Modelling in Z limits my options for turntables. The Märklin and Rokuhan are way over what I can afford (or would be willing to pay). Peco or Atlas versions to convert would be too pricey to import. So, I looked at scratch-building options, and that does seem to be an easy way to solve a lot of problems.

    I can look at prototypes suitable for the size of the station, and make it the proper size. I can also look at how the prototype is constructed and make a proper looking turntable without having to do major rework on a very expensive piece.

    I need manual analogue control, no DCC. No need for a motor.

    Having searched the Internet extensively, I have found that the phono-plug for pivot and power seem to be the best solution. For such a tiny scale as Z it will be large enough to be a steady pivot. The construction of turntable, pit and so on, isn't a difficult thing to do.

    It's the wirering and how to turn it I need some help with.

    From what I understand, one wire goes to one rail, the other goes to the other rail on the turntable track. The connector is then wired to a DPDT switch so I can change polarity.
    But, what about the spurs into the engine shed? Do they have separate power (block wirering) or do they get their power from the turntable? What about the tracks leading onto the turntable? Anything I need to consider there?

    Then the question of turning it. Crank with sprockets and gears, or some kind of pulley system?

    I'm thinking indexing can be done using some kind of notches and a ball with a spring (sorry, I'm not sure what it's called) that falls into place when the track is aligned, but will easily move over to the next one when I turn it. I would be able to feel the "getting into position" for each track, and it would hold it steady until I move it again.

    I'm thinking that my questions aren't scale specific, so I'm hoping for answers from anyone with experience, no matter what scale you model.
     
  2. Reptilian Feline

    Reptilian Feline TrainBoard Member

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    Well... I hope I'm not asking too many questions.
    Anyway... I had a chance to test a phono plug and jack today... and they really are hard to turn. I even ended up unscrewing them from their outer casings. I have no idea how others have made this work, but I can't see it as a viable option... unless you don't connect them properly.

    So, I had a thinking session (at the beach... it's really summer hot here), and thought that I could power the track on the turntable from the different spurs instead. I have to make sure no spurs are exactly opposite each other, but with a scratch built turntable that won't be a problem. If I section up the circular rail at the bottom edge of the pit, I can run wires to the rails and then have something to pick up the power from the rail and connect that to the turntable track. I think that would solve all problems, except on how to manually turn it around without using my hand on the layout.

    What do you all think?
     
  3. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    With analog DC, the roundhouse tracks each will need to be fed power. An SPST switch to kill one rail is all you need there.
     
  4. rray

    rray Staff Member

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    The cheapest solution is to buy the small $30 Peco N Scale turntable, and just lay Z Scale track on top. Solder feeders from the pit wiper contacts. The Peco has a split ring wiper under the bridge. As far as motorizing, there are guys who use Arduino to control stepper motors, which the whole controller can be purchased for around $20, Arduino, motor shield, and motor. Fairly easy learning curve to program, modify someone elses code, and use switches connected to grounded resistors and Arduino inputs to index to each bridge position. I would expect that for under $75 you can have a full featured auto-reversing indexing turntable... After investing in the learning curve to do it.
     
  5. Reptilian Feline

    Reptilian Feline TrainBoard Member

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    Well rray, I did find that the Peco NB-55 manual turntable is available in Sweden... pretty nicely priced too. However, I am not going the DCC route with or without Arduino, so even though I love programming stuff, this layout of mine will be more old school. Still, even though some have some not so nice things to say about the Peco turntable, it might be an option for getting things started. I'm worrying it might be too big in size though, for a British WW2 era layout?

    I think it's time to find that booklet on block wirering... and see what my two controllers are giving out when it comes to power... it's been years since I last saw them... and find the right kind of dip switches... I've found on-off-on ones of various looks... but how do I know I find the right ones?
     
  6. rray

    rray Staff Member

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    With the Peco, you can use 0-5-0 operation on it, and the split rail wiper will automatically keep the polarity correct, so no fancy wiring. I have one of them that I modified for Z Scale, and it can be as simple or as complex as you want, and you cannot beat the price. As far as too big, it's the smallest N Scale turntable you can buy, and it's bridge will just handle a Marklin Mikado with tender.

    For anything smaller, you would have to scratch build it, think Peanut Butter Jar Lid size. There are lots of things you can use to build one with.
     
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  7. Reptilian Feline

    Reptilian Feline TrainBoard Member

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    I looked up the size of the Märklin Z turntable, because that's what I've got in my XTracCad software. I can't add Peco N scale items to the Z-scale layout in the software. It looks like the Märklin has a similar enough footprint to the Peco N scale one, so my planning doesn't get too way off. I'll use the Peco N as a backup, if I can't get a scratch built one going. I like making things my own way, and in this case, I have a theory I'd like to test as well. It might fail, so the Peco one will certainly be the backup. Thanks for the help, rray!
     
  8. Reptilian Feline

    Reptilian Feline TrainBoard Member

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    It's important to look through your stuff once in a while. Turns out I have a Peco N turntable that is still in its box. I bought it when I was trying to put together my N scale layout. Problem solved! Now I just need to read up on converting it to Z and how to wire the layout properly.
     

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