ATLANTIC CENTRALThe CMR turntable bridge rides on the pit rails and floats on a drive block on the shaft, eliminating all such woes. Sheldon
Brian
My Layout Plan
Interesting new Plan Consideration
railandsail Lakeshore Sub Make sure you get it perfectly perpendicular and in the center of the bridge or you have to do it over. ( Had to do it twice). Scott Sonntag Exactly the reason that I said you need to avoid the very rigid connection between the drive shaft and the bridge deck at the CENTER. I believe I made a posting about that?
Lakeshore Sub Make sure you get it perfectly perpendicular and in the center of the bridge or you have to do it over. ( Had to do it twice). Scott Sonntag
Exactly the reason that I said you need to avoid the very rigid connection between the drive shaft and the bridge deck at the CENTER. I believe I made a posting about that?
The CMR turntable bridge rides on the pit rails and floats on a drive block on the shaft, eliminating all such woes.
Sheldon
Fred, I've done extactly that for a small turntable using an Atlast plate girder bridge and 1/4 phono plug. Bob Hayden did an article a long time ago about adding a turnatble to the Carabasett and Dead River using an N-scale atlas bridge so I just made it out of a bigger bridge. I bent the leads of the plug at right angles and epoxied the plug right to the bottom of the bridge. Make sure you get it perfectly perpendicular and in the center of the bridge or you have to do it over. ( Had to do it twice).
Scott Sonntag
I have never actually tried it, but I always thought a decent 1/4" phono plug/socket would make a good center bearing/current transfer for up to about 9" diameter. Wouldn't have to worry about the pit rail being so perfect - just a support to keep the rails level, as in older prototype turntables. Of course, I probably read about this idea somewhere before. I doubt it's original with me.
I believe Carl Arendt used a CD and CD drive (motor removed) as the basis for a 5" turntable.
A Lazy Susan could be a good starting point for a large turntable. Again, not original with me.
And finally, now that very good bearings are cheap for skate board use, skateboard bearings and axles and possibly wheels - at your local Walmart.
just some ideas
Fred W
Marc_Magnus Now because expanding the layout I need a third one.
Now because expanding the layout I need a third one.
Did you see how I made this new turntable pit over here,...with just PVC board and a router,...
New Turntable PitI 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 from several different options), and bent into a circle to fit that round trench I was cutting 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 way 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 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 pit 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. ...test fitting .....test fitting 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. That little black piece under the track sitting on the plywood there is a thin sheet of metal like that I am going to cut a much larger piece to make a base plate for my roundhouse,...so the roundhouse and its feeder tracks, pits, and raised floors will all be sitting on a common base plate that can easily removed from the layout to complete greater detail at a later date, and/or if I need to work on the viaduct and city scenes in the background. Interestingly the turntable bridge is also readily removable from the scene,...per the design of the Diamond Scale turntable itself.
New Turntable PitI 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 from several different options), and bent into a circle to fit that round trench I was cutting 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 way 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 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 pit 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.
...test fitting
.....test fitting
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. That little black piece under the track sitting on the plywood there is a thin sheet of metal like that I am going to cut a much larger piece to make a base plate for my roundhouse,...so the roundhouse and its feeder tracks, pits, and raised floors will all be sitting on a common base plate that can easily removed from the layout to complete greater detail at a later date, and/or if I need to work on the viaduct and city scenes in the background. Interestingly the turntable bridge is also readily removable from the scene,...per the design of the Diamond Scale turntable itself.
And I can show you how to build the bridge deck with Roco curved cord bridge parts and Atlas girder bridge parts.
SeeYou190A good turntable is badly needed, and yes, stepper-motors are the best solution for perfect indexing.
i added a cheap optical encoder to the old $50 Walthers turntable for the DIYer
Adding Encoder to Older Walthers Turntable to Support Indexing with PID Control
greg - Philadelphia & Reading / Reading
I'm very happy with my CMR 135' turntable, and have never needed indexing.
The momentary switch allows you to jog it into alignment just like the real ones did.
I have always located turntables close enough to the layout edge to be able to do that.
Marc_MagnusAnyway this thread has revealed it's time to have a good producer of TT with reliable motors and controls which is now easy with like step by step motors
A good turntable is badly needed, and yes, stepper-motors are the best solution for perfect indexing.
Unfortunately, I doubt there is much of a market for a bulletproof $600.00 HO scale turntable.
I am happy with my align-by-eye Bowser turntables.
-Kevin
Living the dream.
Yes this thread is about Walthers turntable, which seeems the logic choice for many, but with finally a lot of troubles for the most.
I own myself a CMR N scale 135 turntable and it's a real bullet proof turntable.
I have also an heavily modified old Arnold Rapido turntable, I us e for a small terminal with small switchers locomotives.
Walthers is not my cup of thea, the rail pit don't exist in N scale is just a gear track; and I didn't want to buy a non reliable turntable which seems relly the case with Walthers one.
CMR turntable in N scale isn't offered anymore.
Diamond scale is going to an end probably and I' not sure a N scale one in any case
What about AAA turntable, are there still existing and in buisiness?
Anyway this thread has revealed it's time to have a good producer of TT with reliable motors and controls which is now easy with like step by step motors
The turntable on the N scale boxcar layout I built for Scale Rails Of Southwest Florida back in the 1990s was interesting.
The whole thing was built from the main shaft, front housing, and input coupling of a scrapped Cummins PTG fuel pump. The bridge was just fastened to the input coupling and it was perfect.
Powered by a finger and aligned by eye like Doctor Wayne's. No $$$ to make. I really wish I had pictures.
doctorwayne.....excerpt I scratchbuilt this one from a block of wood and a couple of cut-apart Atlas through girder bridges from the "used" table at my LHS. The handrails are leftovers from Athearn BlueBox diesels, and the bridge wheels are from my "parts department". I was originally going to power it through an electrical hand-mixer, but opted to simply use one of the beater shafts for rotation and as a power feed for one bridge rail. The other bridge rail is powered via the wiper shoes on the bridge wheels. The turntable rotation is powered by one finger of my 0-5-0 switcher, with automatic optical indexing... The ring rail is cut from a piece of Atlas flex track, and its support and the pit bottom is plywood, while the pit wall is a piece of 1/8" Masonite. Total outlay was, I think, about four bucks for the two Atlas bridges, while everything else was on-hand, left over from other projects.... The turntable is very easy to use and very reliable, with no maintenance required. I'm very seriously considering the same solution for the turntable shown in the first two photos, if I can't fix the problems with the out-of-round bridge wheels. Wayne
I scratchbuilt this one from a block of wood and a couple of cut-apart Atlas through girder bridges from the "used" table at my LHS. The handrails are leftovers from Athearn BlueBox diesels, and the bridge wheels are from my "parts department". I was originally going to power it through an electrical hand-mixer, but opted to simply use one of the beater shafts for rotation and as a power feed for one bridge rail. The other bridge rail is powered via the wiper shoes on the bridge wheels. The turntable rotation is powered by one finger of my 0-5-0 switcher, with automatic optical indexing...
The ring rail is cut from a piece of Atlas flex track, and its support and the pit bottom is plywood, while the pit wall is a piece of 1/8" Masonite. Total outlay was, I think, about four bucks for the two Atlas bridges, while everything else was on-hand, left over from other projects....
The turntable is very easy to use and very reliable, with no maintenance required. I'm very seriously considering the same solution for the turntable shown in the first two photos, if I can't fix the problems with the out-of-round bridge wheels.
Wayne
Nice job Dr Wayne, I did something similiar years ago with the Atlas bridge parts turned upside down, then atlas curved cord bridge parts glued on top.
Can't recall how I did the roller wheels at the outer ends, but I like your solution.
Clearance Between Turntable Bridge and Pit
I think a number of these commerical turntables seek to have this dimension too small,..like this
Why not make this with a little more clearance?
Just the other day I lifted the bridge out in order to place this "Safety First" lettering on the bridge. One nice feature of the Diamond Scale model is that the bridge rides on the pit rail and the bridge can be lifted out very easily for cleaning or repairs. gmpullman
gmpullman
I like this feature as well.
It also disconnects the bridge from a direct, rigid connection with the central shaft,...making the bridge truly ride directly on the pit-ring rail(s),...both ends of the bridge deck!!
Wiring the Turntable
RR_Mel.... Also high on the list is power to the bridge tracks, using the pit rail really is the pits! I use a dummy looking power drop to the bridge tower made from K&S brass rods for one rail and the drive shaft for the other rail. Positive power to the rails, I’ve never had so much as a single glitch to the rails in over ten years. Mel
I like this idea as well.
OdyknuckIt's actually a very smooth runner. I suspect the thrust bearing I installed has a lot to do with it. It does not have indexing however using a Tech 2 its easy enough to control speed to get the bridge alignment
.
I used my Bowser turntable with a three position rotary swicth to select speed and a DPDT toggle to select direction of rotation.
I was very satisfied with it. I hope to have equal performance from the next two.
I never has indexing, aligning by eye was always OK. None of my locomotives are as long as the bridge.
richhotrain I have had the Walthers 130' turntable for 15 years now, and it works just fine. So, fear not! Rich
I have had the Walthers 130' turntable for 15 years now, and it works just fine. So, fear not!
Rich
OdyknuckIs yours the DCC model #933-2850?
Alton Junction
So I decided to install the motor unit on the Bowser just to see how it works. It's actually a very smooth runner. I suspect the thrust bearing I installed has a lot to do with it. It does not have indexing however using a Tech 2 its easy enough to control speed to get the bridge alignment. So now I need to make a decision. Leave the Bowser in and finish it up or tear out are the work already done and replace it with the Walthers. Gonna need to sit on that for awhile lol.
I had to shim the ring rail to make the bridge level with the top of the assembly all the way around.
I had to shim the rail the bridge rides on in mutiple place's to get it to be at the same level all the way around the table edge. I bought the turntable off Ebay so it's very possible it was a known issue and was not disclosed. I also added a trust bearing between the brass sleeve and the "T"insert in the deck to make it run smoother. It is very close now however my concern it could warp again in a different place and have me chasing my tail. I have not yet installed the drive motor or the Indexing system. I was told by Bowser to not use their setup as it does not work very well and recommended the Daily Electronics unit.
BTW I tested the new Walthers and it appears to work just fine. It does look so much better than the Bowser.
I have one built 15 years ago by AAA turntables. It is indexed in 10 degree increments and has been brutally reliable. I am not sure if Arjay is still making them. I can turn an HO Big Boy on it.
Forgive me here. What do you mean by "run flat"?
My turntables have a plywood bases suspended from a wood deck by a sheet of brass. The depth of this pit is equal all around. The ring rail is on the bottom and the turntable rides on brass rollers on the ring rail.
Was your bridge higher on one side than the other? Was the pit not equally deep all around?
I don't know what work would even be possible if it did not work right. Removing all those brass brads would be quite a task to level the floor.
I am very curious about this.
I put a lot of work into the Bowser to get it to run flat however it is still not right. This is a new layout that I am building and the turntable is not yet finished etc. So now is the time to determine if I want to live with the old technology or use the better looking self indexing Walthers.
wjstix gary233 ATLANTIC CENTRAL The Bachmann models of the 2-6-6-2 are about 95' scale feet long. Sheldon So i need at least a 110’ Turntable. Thanks Nope. Length of the engine body is irrelevent, it's the length of the wheelbase. 95' sounds right for the USRA 2-6-6-2, so it's wheelbase is probably around 85'. It should then fit on a 90' turntable. Best way to work it out for sure is to cut a piece of track to the length turntable you're considering, and try it out on your equipment first. Nice thing about the Atlas HO TT, it uses a 9" turntable bridge so anything that fits on a 9" piece of snaptrack will fit on the turntable.
gary233 ATLANTIC CENTRAL The Bachmann models of the 2-6-6-2 are about 95' scale feet long. Sheldon So i need at least a 110’ Turntable. Thanks
ATLANTIC CENTRAL The Bachmann models of the 2-6-6-2 are about 95' scale feet long. Sheldon
The Bachmann models of the 2-6-6-2 are about 95' scale feet long.
So i need at least a 110’ Turntable. Thanks
Nope. Length of the engine body is irrelevent, it's the length of the wheelbase. 95' sounds right for the USRA 2-6-6-2, so it's wheelbase is probably around 85'. It should then fit on a 90' turntable.
Best way to work it out for sure is to cut a piece of track to the length turntable you're considering, and try it out on your equipment first. Nice thing about the Atlas HO TT, it uses a 9" turntable bridge so anything that fits on a 9" piece of snaptrack will fit on the turntable.
89.42 feet to be exact, so most likely it could be carefully positioned and turned on a 90' turntable.
Odyknuck I currently have a Bowser installed that has it's own set of issues.
What issues have you had with the Bowser turntable?
I used one on a previous layout with no problems, and I have two tucked away for the next layout.
nealknows trainnut1250 Atlas can be modified if you are handy. What needs to be done to the Atlas Turntable. I have one of the ones with 21 tracks. Need to get the turntable motor. What would I need to modify it other than to add an outo reverser to the turntable track. I run DCC. Thanks! Neal
trainnut1250 Atlas can be modified if you are handy.
Atlas can be modified if you are handy.
What needs to be done to the Atlas Turntable. I have one of the ones with 21 tracks. Need to get the turntable motor. What would I need to modify it other than to add an outo reverser to the turntable track. I run DCC.
Thanks!
Neal