Turntable opinions



I'm amazed! Nobody suggested yet that you build your own. If you want a smooth operating TT mechanism, go down to your local bicycle shop and get a front wheel hub. It has a beautiful ball bearing setup to rotate the axle. Mount it in the center of your pit. Next, take a stick and some plaster. Drill a hole through the stick and use it on the axle to create your pit wall and floor. Make a step for the pit track. I would say that you should make your own bridge, but since you already bought one, use it.
As for indexing, Bowser made a neat set. It used a fiber optic under the approach tracks and a LED or small light shining through a pin hole in a mask on the ends of the bridge to trip the power interupt.
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My apologies to the group. I had trouble getting the web site with the construction description to load. It has some neat ideas. I'm changing my comments, but leaving my construction comment (which in some respects is similar to the web site concept) and I'll add another.
A very simple method of powering a turntable with the bicycle hub as a bearing is to attach a large plywood disk with a groove cut in the edge to the bottom end of the axle. Then have another smaller pulley mounted so that a part of the edge sticks out of the side of the layout benchwork. Run a belt between the two. You can then rotate the turntable by hand.
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Wow, I like the idea and once I solve my newly discovered control panel problem, I'll get back to the turntable issue.
Thank you for the help
Carter
wrote:

received
can
indexing?
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When you build you own as described below, how do you handle the electrical pickups for the track?
Carter
wrote:

received
can
indexing?
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Carter Braxton wrote:

The traditional method has been to have the turntable bridge pick up power from the rail running around the base of the turntable pit. You split the ring rail in two, and have a single wiper at each end of the bridge. This method solves the power reversal problem. However it requires great precision in the bridge, the pivot, the wipers, and the ring rail to maintain electrical contact as the bridge rotates. It's doable, but a smoothworking rig takes a lot of care in construction. Or you can make a slip ring mechanism and attach it to the bridge shaft under the table. Or, make the power feed wires long, give them a good service loop, and take a little care not to rotate the turn table in the same direction for more than 10 or 20 turns. Your turntable rotation control needs to stop the bridge very accurately. The locomotive will derail if the bridge track doesn't line up with the roundhouse stall track nearly perfectly. If you are off be less that the width of the railhead, derailment is certain. A manual system (which is prototypical) works if the turntable operator has a good view of both ends of the bridge. An auto stop system needs either a method of adjusting the autostop location, or you have to lay your stall tracks AFTER installing the turntable.
David Starr

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