Electrical connections and pivot axle

I'm always interested in scratch building to save money!  I read an article some time ago in which the author mounted a 1/4 inch audio jack (socket) in the middle of the turntable pit and mounted the corresponding plug pointed downward from the center of the bridge. This would provide a solid point of rotation while also making for an easy way to ensure the bridge rails have continuous power.  For what it's worth!  Good luck on the project; please keep us filled in on your progress!

" I'm thinking of getting the

    You can power both rails with one ring rail, just split it so half feeds one rail and the other half feeds the other rail.The ring rail must be gapped  in spots where the gaps are clear of any radial stall or lead rails....DaveB

I'll second the 1/4" audio jack

I've used one to built the turntable in my staging area. It's merely mounted to a length of plywood with some flex track as it doesn't have to look pretty. The audio plug works very well, keeps the turntable centered with no wobble and provide power to the rails. Plus you can just "unplug" the turntable if needed for maintenance or some such reason.

No matter what you use, good luck.

I like the idea of the 1/4

I like the idea of the 1/4 inch audio jack also the split rail idea using brushes instead of the wheels for electrical pickup from the rail.

http://www.housatonicrr.com/diy_turntable.htm

I'm going to do two

I'm going to do two experiments:

1. Making a base for a bridge assembly so I can remove the bridge in order to facilitate cleaning and maintenance.

2. A bridge that goes directly on the rod.

I've marked where I need to drill a 1/4 inch hole on both for the rod then a larger hole for the 3/8 bearing to fit in:

Now I have to figure out how to drill a hole perpendicular to the bridge surface, as I do not own a drill press, but do have a hand drill.

Any ideas out there?

A Couple Ideas

Here are a couple ideas:

I have one of these with the Craftsman label on it.  You remove the chuck on the drill motor, then screw this thing onto the motor (the shaft at the top is where the drill motor attaches). Works fairly well.

Here's another set of guides offered by Rockler:

http://www.rockler.com/drill-guide-kit?filter=drill%20guide

Thanks Jack, but I'm so low

Thanks Jack, but I'm so low on funds today to get one of those.

Use your bushing as a guide

Put the flange against the wood so the barrel is perpendicular and then use it to guide a drill bit that fits through it without tearing up the inside surface.  You will have a pilot hole that is nearly big enough, and it will be perpendicular. 

Well I managed to get a

Well I managed to get a hole(s) perpendicular to the surface(s) by using the bearing itself as a guide by holding it tight to the surface while drilling.

Here are the two experiments:

The wood tends to get a bit chewed up on the edges of the hole even after using masking tape where I drilled, This caused the lip of the bearing to sit not quite perpendicular so I used a washer under it, which works.

I had to drill out the washers, as they would not fit the bearing without damaging them. I held the washers with a vice grip to drill them.

This is the block for a bridge assembly to go on.

Rog38, we think allike. I

Rog38, we think allike. I just noticed your post. 

After drilling the holes, they were a tad off, but not a problem, as the the depth of the hole required was almost the same depth required for the bearing. At least the first hole worked as a guide for the larger hole.

I'm no drafstman, but I like

I'm no drafstman, but I like to do the math.

Trying to determine if 3/8 space from the pit's floor will be enough for a bridge wiper to pick up the electricity from the rail. I'm thinking of ordering wheels for the underside of the bridge, but have no idea where to get them. I might have to modify n or z scale trucks.

Glad that worked out!

Getting good electrical connections will be a challenge - keep us filled in on your progress, because your solution will be useful to anyone scratch building a turntable, transfer table, etc.!

Will do, Rog.38. This is the

Will do, Rog.38.

This is the area I will be prepping later for the TT i.e., cut out the foam. Also I have to remove old roadbed around the area except for the roadbed for the lead to the TT. In the meantime, have to figure out what would be the best tool to cut out the circle.

I put some ties on the block

I put some ties on the block for the bridge that will have boards over the ties.

The other bridge will be like that seen in the photo at the top of this this thread.

Cutting hole in foam

Very nice work on the bridge ties!

Before cutting any foam I would make reference marks outside the circle so I could locate the exact center of the circle. There is probably a pin prick in the center of the circle from the compass.  I would draw two lines extending beyond the circle, intersecting at the center, approximately 90 degrees apart, like an X. When the foam is cut out I can use the lines to find the exact center pivot point.

I cut a hole for my turntable with a one dollar disposable utility knife.  The snap-off blade can be extended over an inch long.  I first rough-cut near the edge, removed the scrap, then trimmed to the line.  

Almost forgot - I did not build the turntable in place.  It was painful to bend over the layout for that fiddly work.  I cut out a section of foam and built it on the bench, made sure it worked, then transplanted it to the layout.

Thanks Doug, That long tie

Thanks Doug,

That long tie sticking out is what I use for a spacer.

That is a great idea regarding the lines to extending beyond the circle. I'm going to do it tonight.

I'm also no going to build the TT in place.

I'm now figuring a way to make the base from MDF and reinforcing it so it will not warp in the future. One thing I keep in mind is there will be only on point of entry and exit for this TT.

Off I go to draw the lines...

I drew the lines. Note the

I drew the lines. Note the old two curved roadbeds. This module was designed for a longer room, but I had to cut it short to fit a new room so I had to relocate the curved branch line (that leaves the module to the future staging area) farther back.

I think I'll keep the roadbed in place opposite the the entry point where the line is to the left of this photo. It is 8 inches in length and perhaps I can store a flatcar or even an old loco on it. I have no idea if this would be prototypical.

TT construction

Starting in August 1963 MR built a turntable similar to yours. It was part of the Portage Hill and Communipaw  project layout which was reprinted and is also available in their on line archive and on the 75 year CD.

Bill Uffelman

Thanks Bill, will take a

Thanks Bill, will take a look.

Trying to figure a way to

Trying to figure a way to make dolly trucks for the TT bridge. Was counting on ordering a set from Diamond Scale, but no reply from an email I sent also the phone number no longer works.

Extra Track

As far as the extra track off the turntable, yes it would be prototypical, there were usually extra tracks around turntables, beyond what was needed for locomotive storage. The turntable that served my hometown terminal had a short track off one side that had wheel sets stored on it. On an end of the line turntable with no roundhouse, the short track could be used for the purpose of getting the caboose on the other end of the locomotive when it is being turned, so it could be put on the rear of the outbound train. I like your idea of an old loco parked on the stub track, I plan to park a few no longer usable model locomotives on a "dead line" track near the roundhouse like I've seen in old pictures from the 1950's. They would be heavily weathered, with a few parts missing, like the bells, headlights, side rods, and some even had the cabs and tenders missing.

sliders instead of wheels

you could use sliders for contact and height.  The dolly and wheels could be cosmetic

I found the most difficult part was having the TT  bridge turn perfectly level.  This means both the bridge post and receiving socket in the MDF must be exactly at right angles to the approach tracks.  Nothing is perfect so there has to be some slop or flex in the TT pivot, or the pivot and socket needs to be adjusted before fixing it in place.  I do not have perfect answers for this.

Doug, I think I will go with

Doug, I think I will go with the wipers and cosmetic wheels. I will need a stiff piece of shim brass yet not too stiff so to be able to adjust it.

This person seems to have done without wheels.

http://pmrr.org/Structures/Turntable/index4.htm

Moe line, thank you for the

Moe line, thank you for the informative reply. I do like the idea of having the option of using it for a caboose.