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My Diamond Scale Turntable - The Early Years

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My Diamond Scale Turntable - The Early Years
Posted by mlehman on Wednesday, April 11, 2018 10:00 PM

Discovered I had a very short message from a fellow on my phone today asking about my Diamond Scale turntable. It'll try to remember to call tomorrow, but it's kind of late to be calling people now from here. In the mean time, perhaps these pics will help. This is pretty much the documentation on the TT, a 75' long one I use at Durango. The real Durango TT was only 65' but that sounded pretty tight to be hostling big Ks on and off, so I went with 10' longer.

A lot of space is needed for an engine terminal and I got mine in a fairly standard way, inside a loop of track.

A little landscaping goes a long way. Sculptamold is the secret tosmoothing everything together as seamlessly as possible.

Low angle view of C class turning

Here's the DS bridge upside down

I made the handrails out of brassstock. It's not exact, but closely resembles the Durango TT bridge.

 

 

Mike Lehman

Urbana, IL

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Posted by Southgate on Wednesday, April 11, 2018 11:33 PM

Nice work, Mike. I like the dirt ground in the pit. Dan

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Posted by gmpullman on Thursday, April 12, 2018 1:05 AM

mlehman
This is pretty much the documentation on the TT, a 75' long one I use at Durango.

Do you need the instruction sheets, Mike? I still have mine from my 120 foot Diamond turntable. I could post them if you need a copy.

Regards, Ed

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Posted by mlehman on Thursday, April 12, 2018 3:37 AM

Dan,

Thanks for your kind comments.

gmpullman
Do you need the instruction sheets, Mike?

Hi Ed,

Nah, I'm just mumbling along today. Got my instructions somewhere. The fellow was asking about what I'd documented on my build basically. All I really have are some pics in the backup harddrive from before I joined imageshack.

If anyone else has pics of a Dimaond Scale TT build, please post them up. The DS seems a little mystical, because you do have to build it yourself - accurately - and it's been on and off availabiity in the market. Basically, it's like a lot of old kits - you're scratchbuilding with instructions.

Mike Lehman

Urbana, IL

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Posted by railandsail on Wednesday, February 26, 2020 3:44 PM

I have a 134 foot diamond scale turntable I purchased a number of years ago from an estate sale being sold off at the Timonium train show. It was all in a big box and upon cursory inspection everything looked in good order. I left it in that original box for a number of years until it be brought out for installation on my new layout.

Yesterday I unpacked it to get ready to mount it into its place on my new layout. I've discovered that the composite board onto which the pit is attached appears to have some warpage, and a few small cracks in the in the pitwall sides. I looked up the description of this piece and found this,  "Factory-cast pit; pit walls with ring rail ties are Hydrocal, directly cast onto a composition wood base".

It appears as though this composite wood base got damp somewhere along the line, resulting in this warpage.

Where might I find suggestions as to how I might best remedy this situation?,...reinforce that composition board such that the pit is 'fair' and level, or somehow replace that composite base with 3/4 top grade plywood?? I'm not sure how I could 'detach' that hydrocal pit from the original composite board??

I can take some photos. Has anyone else run into such a problem??

Brian

 

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Posted by SeeYou190 on Wednesday, February 26, 2020 3:58 PM

railandsail
I can take some photos.

Please post the photos. I have two Bowser turntables that are mainly brass and plywood.

-Kevin

Living the dream.

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Posted by gmpullman on Wednesday, February 26, 2020 3:58 PM

railandsail
Has anyone else run into such a problem??

I haven't run into that problem —

    However, with the base and pit walls compromised (warped and cracked) I would not use it but build a new one using the old one as a pattern.

The ring-rail has to run true as the bridge is actually supported on the rail. Any deviation in this rail will cause endless grief with rail alignment and electrical continuity.

I recall an article where a pit wall could be formed by making a screed which fits into the pivot hole and as you work it around the circumference of the pit it would form the wall and the ledge for the rail to sit on.

Once the MDF absorbs too much water there's no going back.

Good Luck, Ed

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Posted by SeeYou190 on Wednesday, February 26, 2020 4:04 PM

gmpullman
I recall an article where a pit wall could be formed by making a screed which fits into the pivot hole and as you work it around the circumference of the pit it would form the wall and the ledge for the rail to sit on.

I remember that article too. I was thinking of doing that to make the pit floor of my Bowser turntables look more like the real thing. I also hope to shorten the bridges by about 1/4" and put some texture on the brass pit walls.

-Kevin

Living the dream.

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Posted by mlehman on Wednesday, February 26, 2020 4:23 PM

Brian,

Hate to be the bearer of bad news, but I doubt you'll be able to salvage the existing composite board base at this point. Not sure what your plans are for powering it, but you need a nice flat mount on the underside so that the shaft is precisely vertical. They use composite board because it has less tendency to warp than similar plywood. I'm a big fan of 3/4" plywood, but for this application the composite board is better stuff.

Not sure if your larger TT is the same basic design, but on my 75' there is a smaller board that is mitered on legs that attach to the bottom of the main board. This provides the mount for the lower shaft. I assume the shaft is in the kit parts you have, but a test fitting will tell you a lot. If it slides in easily and, most importantly, vertically true, then you might be able to salvage it. Odds are that won't happen based on your description. But if it fails this test, you can rest assured you need to go with Plan B.

Now for the cast pit. You say it has small cracks in it. It might be possible to reassemble on a new base, but I'm not sure how to get the paster casting loose from the warped base. I think it's simply cast in place on the board/base, because I see no signs from underneath that there are any nails or screws driven up from below that might have the plaster cast round them to give a mechanical bond.

If you're satisfied the current board is too far gone, you might soak everything in water to see if it releases the bond between the wood and plaster. Not sure what results you will have, but if it's otherwise gonna be trashed, why not? Nothing to lose then.

If you cast a new pit, it has to be really accurate in terms of it being centered on whatever you put together for a base to hold the shaft and drive. There is probably less than 1/16" clearance all around between the pit wall and the bridge end.

If I was DIYing things, I'd not cast the ties for the ring rail, but lay my own after casting the pit. It sits about 1/2" in from the wall, but the exact location depends on the relationship between the bridge end and the roller assembly underneath.

Finally and very important, the top of the pit wall must be very consistent all around and located properly so that the top of the rail on the assembled bridge matches up consistently with the top of the rail on the finger tracks ringing it.

Personally, I'd build the bridge first, then make a pit/wall to suit it.

That would be only after I contacted Diamond Scale to see if they would be willing to sell you a new one by itself, which might be the easiest way to solve this dilemma neatly.

Mike Lehman

Urbana, IL

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Posted by railandsail on Wednesday, February 26, 2020 4:46 PM

We have a rainy afternoon here in Fla, so photos will have to wait until tomorrow.

I did write an email to Diamond Scale,...but I believe I read somewhere on this forom that they don't read emails,....rather you need to phone them. I think I will do a little more exploratory work before I place a call.

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Posted by railandsail on Sunday, April 26, 2020 10:01 AM

Been thinking about this project on-and-off for several weeks while I went about other projects. I'm building a new pit for it, and finally yesterday my friend brought his router over with the proper size bit I wanted to use. I'm making my new pit out of cellular PVC rather than any type of casting plaster, etc. I'll add some photos and description soon.

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Posted by rrebell on Sunday, April 26, 2020 11:23 AM

First time I seen this thread, you could have used a thick ply undeneath and screwed the composite wood to it, you had nothing to lose. You could save the pit wall by cutting it free with a multi tool if that didn't work. Might be interesting to try even if your already building the new pit. I had a diamond but sold it off once I go a deal on a RTR walthers for $50. One gear had a flaw in it but was able to score two bridges for $20 on e-bay  and one was the right size.

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Posted by railandsail on Monday, April 27, 2020 10:41 AM

I tried something like you suggested,..bolting it back onto the strong, straight plywood I extracted it from. That helped a little bit, but I was satisfied it would be enough. Here are a few photos of the damaged one, and my attempt to 'draw it' back flat with those HD bolts.

 

 

 

 Worked to a fair degree, but I was still not happy with it, nor just getting another plaster one.

I think you going to like my solution for building a new turntable pit,...NO plaster

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Posted by railandsail on Monday, April 27, 2020 10:51 AM

New Turntable Pit
I spend a fair amount of time thinking about how I might construct a new pit for my turntable. The two primary pieces would be the pit floor itself, ...then the pit wall. One thing for sure I was NOT going to utilize plaster. So here is what I came up with.

 

Pit Floor:
Good grade ½” to 3/4” thick plywood was a top choice in my mind, painted to limit any moisture absorption.

I happen to have a nice square piece of 1/2” thick piece of black Sintra board (cellular PVC) I had collected up from the scraps being discarded by a local sign shop. Why not experiment with this first, then I can always return to the plywood alternative. I decided my pit wall was going to be 1/4” thick material, cut out of several different options, and bent into a circle to fit that round trench I would cut into the floor.

I got out the router, installed a ¼” dia bit, and cut my 'trench' into the flat floor board.



Here I will note that I had 2 options,..cut that 'trench' (partial depth into the floor pit),..or just just cut all the thru the pit floor piece forming an inner disc, and an outward retaining hole in that square floor piece of PVC. Either way, both methods would support my ¼” thick vertical pit wall.

Pit Wall:
I had another scrap piece of the black PVC that was 1/4” thick 9” wide, and about 5' long. I needed a strip of it about 1+3/8” wide, the full length to bend around to form my 'pit wall'. At first I thought about cutting it with a saw, but on second thought I though why not use a sharp razor/ box cutter type device making multiple passes,...much cleaner operation.

That relatively thin strip of plastic would be flexible enough to bend into a radius to fit into my trench, but I wanted to trial run it several times, so several in and outs, plus final gluing. I figured it was going to be easier if the strip of wall material had somewhat of a 'natural bend'. I clamped it around my old pit wall casting, and got out my heat gun. Bravo, nice semi-permanent bend. Finally glued in place with PVC glue.

Once all glued into the trench everything became quit rigid,, very happy with result.

Now I just have to cut some more of that 1/4” thick PVC (maybe the white stuff this time) to make a 'shelf' onto with to glue down the pit rail with its ties,...something like shown in the mock-up I did before I started the router cutting.


I can use the same router dimension plate to cut the hole in my main plywood deck that this turntable assembly fits into.

 

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Posted by rrebell on Monday, April 27, 2020 10:59 AM

Not all your pics showed but I get the jest. Looks like the original was warped more than I thought. Still after all done and said I would multi tool the plaster off the wood just to see if it would work, might help someone else.

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Posted by mlehman on Monday, April 27, 2020 11:16 AM

Nice save with that neat idea on making a good pit wall.

I'd say you have to be very, very lucky to have fudged the original mess into shape to make it operational. A turntable needs things to be right on, not sloppy on. Once MDF or similar chip board gets wet, game over, as it swells and warps, not consistently but in several directions at once.

Mike Lehman

Urbana, IL

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Posted by El Capitan on Friday, October 23, 2020 1:18 AM

Hi Ed,

I purchased a 135' turntable a while back and somehow misplaced the instructions somewhere. If you could send me a copy (pdf) of yours, that would be great.

Regards

Alain Kap, MMR

Saarburg, Germany

Alain
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Posted by gmpullman on Friday, October 23, 2020 9:00 AM

El Capitan
If you could send me a copy (pdf) of yours, that would be great.

I will gladly do that, Alain.

Stop by later once I get a chance to scan the pages.

 Q2_on_TT by Edmund, on Flickr

Regards, Ed

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Posted by gmpullman on Saturday, October 24, 2020 12:59 PM

Here are the pages of the Diamond Scale turntable, Alain.

https://www.flickr.com/photos/gmpullman/albums/72157702106617161

You can download and print right from Flickr using the download icon. (I cleaned up the images a bit at Flickr ).

This should connect you to the .pdf version of the file:

https://www.dropbox.com/s/cg082ewp57zlict/Diamond_0014.pdf?dl=0

Here's a sample of page 1:

 Diamond_0001 by Edmund, on Flickr

Hope that helps, Ed

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Posted by Erik84750 on Wednesday, May 17, 2023 3:55 PM

Three years later and I can have very good use of this topic and the Diamond Scale assembly instructions. So many thanks!!!

Erik

 

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Posted by thomas81z on Thursday, May 18, 2023 6:49 PM

Erik84750

Three years later and I can have very good use of this topic and the Diamond Scale assembly instructions. So many thanks!!!

Erik

 

 

I had to buy the new 130' walthers turntable now just to figure out where to put it  

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Posted by BobR50 on Monday, May 22, 2023 12:08 PM

Mike,

 

If you still have those instructions for this diamond scale turntable, I sure could use a copy.

 

Thanks,

Bob

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