Nice looking

Did you build it or buy it whole ready to install or as a kit? And it looks like it is bolted in?

Jack

Very nice! Did you make it?

Very nice! Did you make it? Is it a kit or did you build it from scratch? The pit looks like the type made by Diamond Scale.

I'm short on funds so I'm attempting to make one from scratch.

http://model-railroad-hobbyist.com/node/29144

Yet another turntable, continued

The CPR 70-foot turntable has a characteristic shape that has always appealed to me (and my prototype is CP).   After a long and fruitless search I finally decided to see if I could fake it using a Diamond Scale 65-foot kit and a couple of cut-down Micro Engineering 50' Deck Girder Bridges.

65 feet is just long enough to turn a D4g 4-6-0, and if I don't look too closely it gives a reasonable impression of the CP turntable.  The pit is still in its original state, and compressed-air piping and motor are yet to be constructed.  The Diamond Scale kit comes with a horizontal air motor, but I'm going to try to persuade a couple of Kentron brass brake cylinders to turn into the vertical version.

The grey lumps are four carriage bolts used to secure the base of the Diamond Scale kit to the underside of the layout.  We'll see if they can be hidden; if not, some flat-heads will be in order.

I replaced the Diamond-Scale shaft with a piece of 5/16" SS thick-wall tube so I can pass wires from the rails down to a slip ring unit.  I had to true up the outside of the SS tube on the lathe, as it was a bit bumpy.   The result works but lacks the precise feel of the the Diamond Scale mechanism. 

David

David, What a superb job you

David, What a superb job you did on that TT and especially the bridge. 

Yet another turntable, continued again

Thank you for the good words. 

Here's the underside.  The brass shaft on the right goes out to a crank on the fascia.  The black plastic thingy is the slip-ring.  It appears to have provision for three circuits, but I wired them all in parallel.  The OD of the slip-ring shaft is 5/16", exactly the same as the Diamond Scale shaft.  Connection is via an inch and a half of 5/16"  diesel fuel hose slit from end to end to let all of the wires out - loose ends still need organizing.  Many will recognize the Tam Valley Dual Frog Juicer which does an excellent job of reversing track polarity on the turntable.

I can certainly recommend the Diamond Scale line of turntables.  Well made, with a smooth mechanism. 

David

< edit> Reference to this particular slip-ring appeared earlier on MRH:

https://forum.mrhmag.com/post/slip-ring-for-scratch-built-turntable-12196762

Wow! That's superb. I wish I

Wow! That's superb. I wish I had the time, patience, and funds for such a project. Perhaps some day I'll replace the current TT I'm working on. I should have never sold my Diamond Scale TT years ago. I though I'd never would need one again, as I thought I'd never have the space again for a layout. Live and learn; c'est la vie.

Thanks for sharing, David

Diamond Scale Turntables are nice...

Mine took a bit of fussing to get it true and level, but it was worth it. I added a Digitrax auto-reverser, built an adjustable two-speed controller (no auto-indexing, lined up by eye, with a push button to nudge it into position). There are two surface-mount LEDs on the bridge arch. Power fed from the ring rail (wipers added) and the arch. Rather than using the wood railing, I made railing from Tichy phosphor-bronze wire to stand up to the inevitable bumps that have already occurred. Weathering needed, of course.

Diamond Scale

Took me a minute to spot the alligator clip feeding the arch!  The bright yellow finally helped.

I guess if there's one problem, it's the tweaking needed to optimize the positions of the dollies and the need to re-tweak from time to time.  No, two problems: if you look at the underside, the set screw for the main drive gear is 'way inside the box supporting the shaft, and it's a very small set screw.  I use a hemostat to grab the little Allen key.

I'll be interested to see pit weathering jobs...

David

Looks good, jlwitt.I like

Looks good, jlwitt.

I like the modifications.

I found this photo of my long gone layout from the 90s with my Diamond Scale TT. Note the aluminum pole and a very fine stiff wire going to the arch.

Thanks...

One thing to be careful about with these; whatever alloy they use to make the metal castings can be liquefied by a soldering iron if you are not VERY VERY careful...I wanted to solder the parts rather than epoxy them, and almost had a disaster. 

Hopefully I won't have to remove it...

It could be pulled out from below if worst came to worst, but I really hope I never have to...I built the layout high enough that I can roll under on a wheeled chair to work underneath (plus it is almost at eye level when standing).

arch and motor

This turntable is (supposedly) driven by a motor running on compressed air, either from the locomotive or the roundhouse supply fed via the arch.  Missing are the two poles to support the overhead air line.

The little gizmo on the right-hand end of the turntable bridge is the air-operated drive motor.  It's supposed to look like this:

That works out to about 1/2" high in HO, so a bit of the detail is missing in the model:

The gears, drive wheel, and pillow blocks came from the Diamond Scale kit, which has a horizontal electric motor driven version.  The two cylinders started out as Kemtron locomotive brake cylinders.

I took that shot of the CP air motor on a winter day somewhere in Quebec about forty years ago and ever since have looked forward to modelling it in HO.  I think it worked out, even if I left out the valve rods.

David

Good to know jlwitt. I'll be

Good to know jlwitt. I'll be careful when installing Diamond Scale dolly trucks on my next TT's bridge.