I recently read somewhere in a RR magazine article a rather cryptic remark to the effect that there were not really any reliable or satisfactory results for turntable indexing. Can this be true? I am anxious to construct a Walthers 90 ft motorized turntable I recently purchased but have no information or details about indexing. Where can I find reliable detailed decriptions and/or instructions for understanding and completing my indexing project?? I’m only a novice at electrical projects. Can anyone out there point me in the right direction???
Any and all assistance would be grestly appreciated.
I just bought the built up 90’ Walthers turntable from Cherry Creek Hobbies on sale. I won’t have it until today or tomorrow. I did a bit of research before I pulled the trigger on this unit. Most everything I read that was negative was about the older kit version of this turntable.
On the other hand, The BUILT UP unit that costs a king’s ransom (even with CC Hobbies nice discount) has received very good reviews. I can’t be yet because I haven’t had any experience with mine yet, but over the next few weeks I’ll know more. All I can say is the guys that have them seem to love the darn things, so I will keep my fingers crossed.
I have had both, and trust me on this, the newer indexed version ($$$) is so far out in front it ain’t even funny. Both are the 90’ versions, and the difference is, in my opinion, well worth the many more dollars.
For one, the device actually works,…well. Secondly, unless you really have a hankering to build kits, especially the 90’er, all you do is read instructions, cut out the disk on your bench, insert the TT pit, program it, and away you go. All up, including searching locally for a 16v AC power supply (it doesn’t come with one), I think it took about one hour. The kit is several hours to build, depending on how finicky you are…and skilled…and handy, since it has problems…and then you have to do the installation and powering, including a DPDT or a power reversing unit. The indexed model uses a split ring design on the wipers for the track rails, so it needs no reverser.
Were they referring to models, or prototype turntables? In either case, they’re dead wrong.
Mechanical indexing systems (tapered deadbolt type) were described in the model press over half a century ago - they worked then and should work now. Later devices used photoelectric indexing or microswitches, which could be made almost perfect with a little bit of fine tuning. Then, of course, there is the Atlas Geneva motion system - not very prototypical, but the indexing is dead-on, every time.
Maybe the writer meant that there were no systems THAT HE KNEW OF that were reliable. Depending on his level of ignorance, that is entirely possible.
Chuck (modeling Central Japan in September, 1964 - with one turntable indexed with the Mark I mod 0 eyeball)
The Diamond scale unit is quite accurate and reliable but to build it is not for the faint of heart. I also installed an infrared detector unit for a freind and it slowly creeps off indexing due to play on the pivot. Was hard to get set up too. Just looking at Walthers unit in the catalog looks like it might be the way to go.Spend the bucks on a good unit and don’t spend three days under the table adjusting the indexing and yelling at your helper on top,demanding to know if the hundredth adjustment is right yet.
oops,I missed the point about you already buying the Walthers unit. Welcome to the forum by the way.
I guess at this point I’m not much help, But I saw an ad in MR’s new Realistic magazine for an outfit called Digitalloco.com. I looked up the site and they have an electronic idexer for sale for $40 but not much info about it You may want to drop them an e-mail and get some info. I’m assuming their unit works with photocells as thats what they also offer.
Take some short lengths of thin brass - as this narrative proceeds you will be able to determine how many of these your are going to need - and impress a nipple very close to one end in each piece. Bend these pieces into an L shape; one of these will be affixed to the underside of your turntable bridge and the others to the underside of each indexing location on your trackage leading to the turntable pit. THEY HAVE TO BE AS CLOSE TO CENTERED AS YOU CAN GET THEM!!! You are going to have to drill a bunch of small holes, one at the end of your turntable bridge and the others in the face of your turntable pit at all of the locations you want to index… THESE HOLES ARE GOING TO HAVE TO BE AS CLOSE TO CENTERED AS YOU CAN GET THEM!!! Get yourself a handful of coupler springs and a handful of ball bearings. Configure these: L-Shape - spring being held in place over the nipple you impressed in the brass L Shape - spring holding the ball bearing in place against the turntable wall… Ground the brass L shape on the turntable bridge; connect the other ends to the voltage for an LED and wire everything to an LED indicator mounted on your control panel. As your turntable turns every time these ball bearings co
the info they have shows that it’s not an indexer at all , just a simple controller that makes the turntable rotate in one direction or the other . stopping it in the right place is done by eye and careful control of the speed of the TT . an interesting unit , and maybe worth the price , but not an indexer . expect to pay much more for any commercial system , there are a couple advertised in MR
Thanks ereimer, I was wondering about that. The price seemed almost to good to be true. The company also showed photocells as product so I was assuming they were somehow connected.
OK I went back to the website and here’s what it says. This is not to argue but for info only.
Welcome to Digital Loco
STOP controlling your turntable with a doorbell pushbutton! Check out our new, revolutionary, MSC1 Turntable Positioner/Indexer! It’s an intelligent, microcontroller based design with a single rotary control and status LED for controlling the speed and direction of turntable motion. It’s designed to mount right to your control panel where the yard diagram shows the turntable. Go fast to get near the track, then super slow to creep right up on it. Precise, interactive indexing every time.
i’ve always thought that indexing means some method of automatically stopping the movement of the turntable when it reaches each track around the turntable . i don’t consider manually slowing down the turntable as it approaces a track to be indexing . believe me , if there was someone selling my definition of indexing for $40 i’d be first in line with my credit card in hand !
You can index a system without having a programmable memory into which you can programme pre-determines stop points. Indexing merely means that the device will sense, and is capable of performing a function (stop, go, weld, paint, etc. depending on what the purpose of the indexing is) at, discrete points in a range of motion. So, without actually knowing, my guess is that this device is truly indexed, but you can’t programme it. That would mean you have to orient your approach and bay tracks carefully around the pit so that the two rails precisely stagger, or have their centrelines, directly over the index point.
I like the idea of being able to programme them in where I darned well want 'em. So far, my bridge, after many cycles, has not had to be adjusted or reprogrammed. In honesty, I do have to nudge it about 1/16" at two of the three bay tracks, but that is a minor thing. I could obviate that by clearing out the memory and re-programming once the tracks are perfectly aligned…it takes literally seconds…I am just too lazy.
if my reading of the info on the website is correct then by your definition this product does not index , as it doesn’t stop at discrete points , the stop points are determined by where you stop it by eye , and your control of the speed knob . unless by discrete points you mean every (infinite) point on a circle [:)]
that’s possible . but in that case , what is the definition of indexing ?
maybe i should define what i think this device is doing
it is a variable speed control that allows you to rotate the turntable bridge , and slow it down as it approaches the track you want to use
and my definition of indexing
a method of automatically stopping the turntable rotation at the track you want to use
by my definition indexing is automatic , and the phrase ‘automatic indexing’ is redundant . what is manual indexing ?
let me add at this point that i think this is a pretty neat product , and sells at a decent price for what it does , and if i wanted to manually control where the turntable stops i’d buy one of these . in fact it’s probably a better solution than buying an atlas turntable and burying it under a false pit and having the atlas turn my turntable’s bridge which is my current plan .
Hi All! First off, I must apologize for the somewhat ambiguous nature of my ad and my web site. I will rectify this soon.
The MSC1 was designed for several purposes: 1) as a turntable positioner (or interactive indexer), 2) a Back-N-Forth controller, and 3) a general purpose motor controller. I actually was inspired to design and build it by my own Walthers 90’ turntable. I was in the process of integrating a stepper motor and microstepping controller, when it occurred to me that all I really wanted was a variable speed motor controller with direction control. It then occurred to me that a small potentiometer with a center detent off position, centered in the control panel’s schematic for the turntable would be too cool! So I designed and built one. It works so well that I decided to offer it for sale. In a few more days, I will post pics of the partially completed control panel on the digitalloco site. Please have a look on 5/13.
I have also tested the MSC1 on the Atlas turntable with the optional motorized unit. Even though the Atlas has an integrated indexing mechanism, the MSC1 allows the Atlas turntable to be moved very slowly, in either direction, for very smooth and precise control.
As a Back-N-Forth controller, the photocells are placed at each end of the BNF track. The loco has smooth ramp-up and ramp-down speed functions at each end, but in between operates at a speed proportional to the rotation of the rotary control. The photocells automatically adjust to varying lighting conditions. At each end, there is a random delay of 10 to 30 seconds before the return trip begins.
Finally, the unit can be used to control the speed and direction of any motor found on any layout, up to 1 Gauge! Good for bridges, carnival rides, anything!
Please give one a try - if you don’t like it for any reason, just return it for a full refund!
thank you for your explanation of your product . i think describing it as a turntable positioner (in addition to it’s other uses) makes the most sense to me , although i’d like to hear your definition of indexing , maybe mine is wrong . maybe “interactive turntable positioner” is even better
interesting that it works with , and improves the operation of , the atlas turntable
what kind of motor would you recommend for turntable use , specifically to turn an SS Ltd. 90’ turntable with a bachmann 4-6-0 as the largest load ?