Well, Well, Well.. How the Turntables..

[crossthedog]

doctorwayne

and a finger tip can move the bridge as needed, once I add some drag on the shaft.

Doc, would you enlarge upon this, please? How do you add drag? Do you put Maxwell's Demon in a box under the layout and have it offer resistance to the shaft turning? If not that (probably not that), how?

-Matt

[doctorwayne]

lone geep

I know Diamond Scale makes turntables but does anyone have experience with these? What other manufacturers make have decent turntables?

I built one for a friend, but that was close to 40 years ago.  I don't know if it still works, though, as he has so many locomotives on his layout, it's difficult to get anything to move.

I have one of Walthers 90'-ers, but I'm not going to motorise it, as it's close to the edge of the layout, and a finger tip can move the bridge as needed, once I add  some drag on the shaft.
I also have a scratchbuilt 89'-er (there wasn't quite enough room to add an extra HO scale foot), and it's also close to the layout's edge and also finger-operated.

A friend recently gave me a large-ish brass locomotive (unpainted and somewhat tarnished, but I mentioned that it was too big to fit onto either of my two turntables, so offered it back to him.  He declined, so I took it apart and made some slight modifications and a few small repairs, then painted it.
Since there was a photo (black & white) of the real one in the locomotives box, all I had to do was research to find the colour of the lettering on the cab and tender.

He suggested that I sell it, in order to buy something more suitable, but I still have eight locomotives to re-build/re-work, to match particular prototypes.
In the meantime, I did give the too-large loco a test run, and it ran fairly well, considering its age...I just might keep it...if I have enough strength to pick it up and manually turn it when needed.
I have what appears to be reasonably suitable yellow lettering for a Pere Marquette 2-8-4, but haven't yet found any info about the colour of the cab's window frames...and, of course, I can always re-letter the loco for one of my layout's made-up road-names too.

Wayne

[trainnut1250]

RE - Diamond scale: They are still in business and taking orders as of a few days ago.  A friend of mine called and spoke to the owner last week. It will take six months to fill my friend's order. In my experience about 10 years ago, it took a year to get the items I ordered. Slow but steady.

 

Guy

[Wazzzy]

I have a HO 130' Diamond Scale I can part with. Contact me off Forum.

[ATLANTIC CENTRAL]

Here are some more pictures:

 

 

 

 

The bridge actually rides on the pit rail, and it uses the traditional spilt pit rail system to power the bridge track, so there is that one magic spot where you cannot have track.

Being a DC operator I like this system because properly positioned, it maintains "east - west" operation relative to the direction switch on the throttle.

My whole layout is designed/wired so that "left is always west, right is always east" from the view of the operator/viewer. The turntable is no different.

Sheldon 

[ATLANTIC CENTRAL]

Pruitt

I need a couple more turntables for my layout, and was considering either the Walthers 90' or the Diamond Scale tables.

Can anyone talk more about the CMR turntables? How were they to build? Easy, difficult, what? 

Anyone have pictures of their motors and the mounting kit?

 

I have the CMR 135' turntable, it was easy enough to build, and it has been upgraded since I built mine to make it a little easier yet.

It is a unique construction process. All CMR kits are lazer cut acrylic plastic. The bottom is a large round etched piece of acrylic, the pit walls are assembled with layers of curved, flat, tab and slot pieces of acrylic.

My only criticism is the railing and power hoop are bulky, oversized. I did not use them, I bought brass parts that were available from Bowser back when I built mine.

Mechcanically it is very strong and well built, the bridge is easily removable.

 

 

I'm not completely sure if he is using the same motor setup. I will take a picture of the motor setup that came with mine years ago. I can find out, I know him personally.

Mine is a gear drive display motor with a direct drive to the drive "T" that the bridge set suggly over, but is easly lifted off. It came with a reverse switch and a "run - off - jog" switch. Works fine as long as you are close enough to see - no indexing.

More pictures in a bit.

I had mine installed and tested on the old layout, but never had the whole roundhouse built or set up.

Sheldon

[Pruitt]

I need a couple more turntables for my layout, and was considering either the Walthers 90' or the Diamond Scale tables.

Can anyone talk more about the CMR turntables? How were they to build? Easy, difficult, what? 

Anyone have pictures of their motors and the mounting kit?

[trainnut1250]

dknelson

 

Lastly and I have mentioned this before, on a layout tour years ago I saw a clever turntable idea.  The turntable was reasonably close to an edge of the layout.  The builder had created a wheel, perhaps of plywood, that was larger than the radius of the turntable pit, and lower than the turntable by a couple of inches, and one edge of that wheel extended beyond the fascia through a slot in the masonite.  The turntable was entirely manual but it was totally unobtrusive.  And no human hand had to touch the turntable model itself.  (Contrast that with something many modelers have done: disable the Geneva mechanism on the classic old Atlas turntable and just turn it by hand.)

Dave Nelson

 

 

Dave,

 

I did exactly that with one of my turntables.

 

Guy

[dknelson]

I too love that handcrank.  It conveys somehow an old school industrial/manual labor feel to it.  Only slightly OT but I have read there were some movable railroad bridges that had electric motors but in case of emergency could also be moved with hand cranks (finely balanced bridges).

To return to the topic, for a time Bowser offered turntables and may yet.  I don't think I ever saw one for sale in a hobby shop, even a shop that sold Bowser products.

Lastly and I have mentioned this before, on a layout tour years ago I saw a clever turntable idea.  The turntable was reasonably close to an edge of the layout.  The builder had created a wheel, perhaps of plywood, that was larger than the radius of the turntable pit, and lower than the turntable by a couple of inches, and one edge of that wheel extended beyond the fascia through a slot in the masonite.  The turntable was entirely manual but it was totally unobtrusive.  And no human hand had to touch the turntable model itself.  (Contrast that with something many modelers have done: disable the Geneva mechanism on the classic old Atlas turntable and just turn it by hand.)

Dave Nelson

[gmpullman]

ATLANTIC CENTRAL

I do like your hand crank drive Ed. Mine has a display motor drive and you just jog it into place - works well too.

Thank you, Sheldon. I started off with a synchronous gearmotor, too. At the time I thought the programmable stepper motor was going to be an improvement and in some ways it was but with that ever-present backlash I was considering ways around that including a jog button with a brake.

After I changed the roundhouse to the Walthers Cornerstone Modern roundhouse I was faced with again reprogramming the stepper motor and that led me to explore other options.

Here is some of the exploratory setups I was playing with:

Turntable_Oblique by Edmund, on Flickr

Turntable_Crown by Edmund, on Flickr

That's interesting about Rob's Trains and his updated page. I can't find much else about his store in Alliance. Google street view shows it in 2018 and it doesn't look too promising in that view. When I was last there in the mid-2000s he had a pretty brisk business.

Regards, Ed

[ATLANTIC CENTRAL]

The price list page has a 2023 update.

http://www.diamond-scale.com/pricelist.htm

But I am completely happy with my CMR turntable.

I do like your hand crank drive Ed. Mine has a display motor drive and you just jog it into place - works well too.

Sheldon

[gmpullman]

ATLANTIC CENTRAL

Aparently still in business selling turntables:

I'm not getting my Master Card out anytime soon...

Diamond_last update by Edmund, on Flickr

ATLANTIC CENTRAL

Is that the same outfit that once sold can motor repower kits under the name "Alliance Locomotive Products - Helix Humper"?

Yes, same guy. I suppose the best course of action for any potential customer would be to telephone Rob Sundberg of Rob's Trains first.

Cheers, Ed

[gmpullman]

Duplicate reply. See below.

[ATLANTIC CENTRAL]

Aparently still in business selling turntables:

http://www.diamond-scale.com/products.htm

Is that the same outfit that once sold can motor repower kits under the name "Alliance Locomotive Products - Helix Humper"?

I bought a bunch of them, they work well.

Sheldon

 

[Morpar]

I have the Walthers 130' turntable and currently the bridge is at Walthers for repair. One of the wires going to the infrared emitter in the bridge (to show home position) wasn't connected so I couldn't get the bridge into the home position. I set a couple of track positions using a pencil mark for a temporary home position and it seems pretty much on the money.

One of the local hobby shops (Train-N-Connection in Greentown, Indiana) has built a custom table based on a Micro-Mark axis for a milling machine (if I recall correctly). Norm said it was actually very easy and more accurate than the Walthers system. Nor sure exactly how he made the pit and bridge, but he and his customer have been pleased with the results.

[gmpullman]

My first and only turntable, other than the ubiquitous Atlas 9-incher, is a 130 foot Diamond Scale model. It has been trouble-free for 28 years. It is a kit but the construction goes well and mine has remained strong and stable.

Early on I used the worm and ring gear supplied in the kit. This was OK but I should have 'engineered' a way to reduce the backlash of the gearing. When the stepper motor indexing system was made available by the New York Railway Supply I bought one of these in 2003 and installed it.

Here's what the NYRS stepper motor looked like:

IMG_1230 by Edmund, on Flickr

And the control interface:

NYRS Turntable Indexer by Edmund, on Flickr

The NYRS system worked fine but never really lived up to my expectations nas still, there was a bit of backlash in the gearing and on a 130' turntable this can translate to 1/8 to 3/16 inch of misalignment at the bridge ends. Programming was time consuming but newer models allow for adjusting individual tracks and my version did not have this but I could have had it upgraded for a fee.

Not long ago I decided to redesign the drive first exploring an enhancement of the original Diamond plastic gears. Then I found a zero-backlash right angle 1:1 drive I had in my stash of 'stuff' that proved to be an ideal starting point for a manual reduction drive. I'm quite satisfied with my latest system. The bridge ends stay aligned and there is practically no deviation of the rail alignment.

Here's my present drive system:

Turntable_drivetrain by Edmund, on Flickr

The operating wheel is fun to spin 

Turntable handwheel by Edmund, on Flickr

Now I'd like to hear from anyone who has purchased a Diamond Scale TT in the last ten years. The last thing I was aware of was that the assets of Diamond were purchased by a fellow at Rob's Trains in Alliance, Ohio, a hobby shop I used to visit on occasion. As far as I know you'd only be able to find a Diamond Scale TT on the used market or auction sites.

Q on Turntable by Edmund, on Flickr

 

Good Luck, Ed

[trainnut1250]

See this thread for a recent discussion on turntables:

https://cs.trains.com/mrr/f/11/t/295056.aspx

I would go with the Walthers built up or maybe the CMR kit...Diamond scale is a box of sitcks and a hydrocal casting for the pit (depending on the style and kit you purchase from them). Their linkage parts are great for scratchbuilding or creating a hand crank for a turntable.

 

You'll get lots of opinions on this,

 

Guy

[lone geep]

Even though I'm farther off from putting up benchwork than I'd like, Im starting to plan out the track with Xtrackcad. In my previous basement apartment setup, I had the Walthers Modern Roundhouse paired with their 90 ft turntable. However, given that I am mostly starting over, I would like to install a larger turntable with this roundhouse. I know walthers makes a 130 ft one but I'm not impressed with the 90 ft one I've built before since it still requires more tinkering to make it work reliably. I know Diamond Scale makes turntables but does anyone have experience with these? What other manufacturers make have decent turntables?

Thanks