Turntable Design and Build

Where users can chronicle their builds. Start one thread and continue to add on to it.

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Glenn Brooks
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Location: Woodinville, Washington

Re: Turntable design

Post by Glenn Brooks » Sat Jun 04, 2016 12:31 am

Thanks Carl,

We dont have any significant frost issues here in the Seattle area, but I have noticed some weird annual hydrologic change in the soils around our house - seasonal foundation heaving in one specific spot in the house, caused by sub surface 'upwelling' from an underground spring. So a similar effect to frost heaves. I think I will go for the deeper range of cement pivot foundation you mention in your post. The 3 or 4 adjusting rods are an excellent idea. Then Hopefully the outer ring support will stay level and not tilt or dive away next spring, causing lateral stress on the outside edges of the table.
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

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RONALD
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Re: Turntable design

Post by RONALD » Sat Jun 04, 2016 7:23 am

Glenn, if you looked at my construction, you see I used a tripod assembly for leveling our turntables. It's for the same reason you use a tripod for a transit, laser, camera, or any other device that must be leveled; four legs or more are difficult to level.

Have you ever seen a surveyor using a quadpod? Of course, you want to make sure each leg of that tripod can carry its estimated load.

Here is what the center support for TT#2 looks like. It is a tripod, as #1, but has a different bearing. I cast and machined that large brass center to hold two 12" Lazy-Susan type of bearings I bought on ebay, they run in an oil-bath and run just as good as the roller bearing used in TT#1.
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6491
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Re: Turntable design

Post by 6491 » Sat Jun 04, 2016 8:57 pm

We have a similar set-up, but we have 9 bolts in ours. Never been a issue in adjusting the level, probably takes a bit longer.
Have a good one....John.
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makinsmoke
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Location: Texas Hill Country

Re: Turntable design

Post by makinsmoke » Sun Jun 05, 2016 6:58 am

The simplest center bearing I've seen is one half
of a pickup axle cut off and mounted vertically in concrete with the hub bolted to the bottom of a
length of 8" channel.

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PRR5406
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Location: Eastern Maine

Re: Turntable design

Post by PRR5406 » Tue Jun 07, 2016 5:11 pm

What about using a heavy wheel bearing retired off a truck as the center pivot?
"Always stopping my train, and risking my ankles, with American made, New Balance sneakers."

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makinsmoke
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Location: Texas Hill Country

Re: Turntable design

Post by makinsmoke » Tue Jun 07, 2016 10:30 pm

Yes, same thing. Just keep the axle half to give you something to concrete into the ground for lateral support.

Glenn Brooks
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Location: Woodinville, Washington

Re: Turntable design

Post by Glenn Brooks » Tue Jun 07, 2016 11:56 pm

Cool idea. I've actually just run across an OOOOld 20' travel trailer frame and axle assembly, free If I remove it from the brier patch back of a farmers field. The axle and wheel assembly looks massive. No idea if it still turns or not. Maybe will assess the 'rust factor ' and think about bringing it home. Still have room behind the shop for storing old RR junk the wife doesn't want to look at in the yard...
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

chooch
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Location: East Central Florida

Re: Turntable design

Post by chooch » Sun Jun 12, 2016 8:57 pm

Years ago I saw several old (real) gas station auto lifts used for turntables. Just a mention as I have not seen it mentioned here.

Great turntable article. Very interesting, informative and good ideas.
Thank you all. chooch

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Loco112
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Location: Dallas ,Texas. USA

Re: Turntable design

Post by Loco112 » Mon Jun 13, 2016 12:32 am

Bitter Creek & Western uses 1/2 of a 50,000 truck trailer axle as their center pivot, check the photos. That's also what Im planning to use. The seal type and location (s), should determine whether the hub is outside up or outside down in its placement.

You could use a smaller hub, say something closer to 10,000 would still be overkill.
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Glenn Brooks
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Location: Woodinville, Washington

Re: 12" ga Turntable design

Post by Glenn Brooks » Wed Jun 22, 2016 3:24 am

Well, started building the turn table yesterday. Decided to use existing/on hand/freebe materials to the extent possible. So thanks to Craigs list/free stuff have acquired free 60LF of 3x10" lightweight I beam - by cutting down an old 40' RV trailer frame, and a bunch of large cement retaining wall blocks. Seen below, laid out to form the basic circular shape of the turnstile.

I've discovered it takes a certain amount of jaundice to scrounge through all the unlikely freebe giveaways to find what you need. How much demand is there anyway for old stumps (u dig Fer Cris sakes!!) and used tires. Gawd, what garbage shows up there...

Anyway I plan to clean up and weld the trusses to form a 36" x 14' bridge, having four parrell beams for longitudinal support, to lay the ties, track, and safety rail. Again this is for 12" gauge loco and cars. Pivot pin and mounting base , so far will be some old 3" OD shafting that came my way, a few months ago, and some 1" plate that can be machined to accept the pin.

Here my boy and I laid out some of the cement foundation blocks in the initial location. We used twine to set the 14' radius of the table and white spray paint on the ground to mark the circumference.
image.jpeg
Beginning to build the turntable foundation
A second course of cement blocks , with cap stones cemented to the blocks on top will bring the feature up to grade. An inner course of smaller cement blocks will form the walls of the inner retaining wall that holds the ring rail. Then backfill with dirt to hold in place.

The turntable will enable me to offload locos and cars onto sidings for storage next to the shop, and because of space constraints, the turntable table will also be in line with the main circular loop around the property. So hopefully, I will be able to build to a close tolerance, allowing train consists to pass over the table without undue banging and bumping around...
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

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NP317
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Re: Turntable design

Post by NP317 » Wed Jun 22, 2016 9:37 am

Ahhh. The fun begins...
~RN

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Erskine Tramway
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Re: Turntable design

Post by Erskine Tramway » Thu Jun 23, 2016 8:13 am

That looks like a good start, Glenn :D

Mike
Former Locomotive Engineer and Designer, Sandley Light Railway Equipment Works, Inc. and Riverside & Great Northern Railway 1962-77
BN RR Locomotive Engineer 1977-2014, Retired

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