Turntable OO

Has anyone ever built a turntable in OO rather that purchased a commercial pre built one.

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And with an old gramophone motor too. But that was long ago
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"Trev" <trevbowdenATdsl.pipexDOTnet> wrote in message

What 78RPM or 45RPM, ? that must have interesting to watch.
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wrote:
Paul,

I built several in 4mm and N scale many years ago What do you want to know?
Jim.
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Paul wrote:

Not in OO but in HO. I was young and poor and couldn't afford what was on offer, even a kit turntable cost almost two weeks' wages! It was an "armstrong" turntable, ie, one rotated by men pushing on a pole fastened to the end of the bridge. This was used surprisingly often on small tables at the ends of branch lines. With a small engine, well balanced on it, it took very little effort to turn the bridge, which rode on half bogies riding on a circular pit rail.
I found that the trickiest part was the turntable pit, but I used other people's techniques for this, and it worked out well. I built the bridge substructure first: cut a piece of wood the right length, somewhat narrower to allow for adding "girders" on the side, and somewhat shallower to allow for the track on top. I drilled a hole first, then cut it so that the hole was as close to its centre as I could measure, and glued a washer on the bottom to act as a bearing. I inserted a piece of 1/4" steel rod I happened to have (the hole was sized to be a tight fit.) A chunk of very large nail could be used.
I drew the turntable pit, tracks, and roundhouse locations on a piece of plywood and cut it to fit into and against the baseboard of the yard. I drilled a hole at the centre of the turntable pit to clear the centre pin of the bridge. I glued a washer there to act as a bearing, dropped the bridge into it, and used it as a compass, by taping a sharp nail at each end, and turning it. The two circles differed a bit, so I sanded the longer end, and redrew the circle, and repeated this until both ends produced the same circle. Then I taped a thick pencil on the end, and drew another circle about 1/4" outside the scratched one - this was the diameter of the pit.
Next, I fastened a piece of plywood underneath where the pit would be, using _unevenly_ spaced screws to ensure alignment later. I used the hole above as a guide to drill a hole through the lower piece, and removed it. Then I cut the turntable pit out as carefully as possible, which wasn't easy with a handheld power jigsaw. I refastened the lower piece, inserted the bridge, and drew another working circle just inside the pit walls. I used this line as a guide for gluing "used ties" to the wall of the pit. That's how the prototype lined the pit wall. If you want a "concrete" wall, you'll have to apply some kind of goop to the wall, and use the a bit of wood fastened to the end of the bridge as a trowel.
I then glued half length ties all round the outer edge of the pit, and glued and spiked two half circles of rail in place. I did not build a half bogie to support the bridge, but instead used two pieces of springy brass, which rode on the pit rails, and which were hidden by the girders glued to the sides of the bridge.
The two pieces of rail in the pit were wired to right and left approach rails respectively, the brass wipers ditto to the bridge rails. Thus, the turntable bridge became a reversing switch, very handy. I added details, paint, weathering, and so on, and it looked just fine. I planned to motorise it eventually, but didn't, just used my fingers and a proper armstrong pole to turn it around, as the table was close to the front of the layout. It's long gone, of course, but it worked.
HTH
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This can still be seen at the Didcot Railway Centre. Part of the Open Day routine is to run a GWR 7F 2-8-0 up to the table, and turn it by hand. On some occasions they use the rotating crank handles, on others they just push the bars. A 7F is not small, and though I've watched it dozens of times, I still can't work out how they shift that weight.
(I'm usually watching from the restored saloons Queen Mary and Princess Elizabeth, while enjoying a leisurely afternoon tea. It's amazing how one's digestion is greatly improved by watching other chaps putting their backs into the job!)
Cheers, Steve
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Steve W wrote:

The turntable runs on roller bearings, and if the loco is placed so that its weight balanced equally from the bridge centre, there's little rolling resistance.
HTH
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Steve W wrote:

PS: A 7F is small by N. American standards. Sorry 'bout that!
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Of course, because there's so much more room.
Here in the Toronto-Montreal corridor we have ~120 car freight trains (e.g. double-stacked containers or 3-decker auto carriers) and inter-city passenger trains with as few as 3 coaches (but the coaches are bigger!)
--
Martin S.

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American bankruptcies are bigger, but better? Think of Enron. Mind you, I shouldn't complain, the Sarbanes-Oxley Act, Congress's knee-jerk reaction to Enron, is giving me plenty of no-brainer-type work to do (I suppose that's because American executives generally have no brains). (No smiley, because I'm serious).
--
Jane
OO in the garden http://www.yddraiggoch.demon.co.uk/railway/railway.html
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Jane Sullivan wrote:

I agree, but then too many of them have been "educated" at Harvard and Yale, etc, with prior stints at Groton, Amherst, and similar stultifiers.
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