REVISING the OGR forum's MAJOR MODIFICATION to the BOWSER TURNTABLE

[Anonymous]

The late Cary Bassani posted a fabulous article in the OGR forum on rebuilding the Bowser turntable to make it operate properly. However, since OGR "upgraded" their forum old threads can be hard to find, like his.

After reading the late Mr. Bassani's thread, I decided that of the many modifications he described, the motor mount was not the modification that I wanted to make. And of course being a former engineer, as you all know, we just love to change things!

So I redesigned the motor mount in a way that I think is both easier to build and less obtrusive. Before I go further, again, Cary’s thread also included a number of other improvements that can be made in addition to the motor mount revision that will be described in this thread.

I am new to this forum; so let me say that my earlier training is as a structural engineer. And early in my legal career, I wrote electro-mechanical patents, so my writing style tends on the more detailed side. Photograph will be coming in Part 2 of this thread, assuming I can figure out how to do that in this forum.

I had intended to place this article in the OGR forum before I was told that I would have to pay to do so. Oh well! Maybe a well-intention OGR’er will post this there. If they do understand that that act infringes on my copyright of this article. However, any CTT member may copy freely for their own use.

To begin again, the Bowser Turntable is by far the cheapest, next to building your own, ( which I have using Lionel's TT), turntable on the market; as compared to for example AAAs or Diamond Scales. Both of which are many more times the cost of the Bowser and more complex as well. Vernon Peachey has one too. He had an advertisement in the February 2004 issue of OGR. The listed phone number is 540-948-5968 e-mail address is [e-mail]. I understand that Ross Custom Switches may be building a turntable kit at some point too, to go along with their soon to be released transfer table.

I decided on the Bowser Turntable because it was simple to build. However the biggest drawback was the motor design that spun the bridge. The big engines were too heavy for the table and the motor design of the Bowser was not strong enough to turn the bridge with these engines. It slipped and stuttered. Not good no clear solution. Enter the surplus dish antenna 12 VDC Gear Motor.

All Electronics’ Corp (www.allelectronics.com, search for DCM-178) Gear motor was originally priced right at $32 and now is available for about $15.00 was intended as a satellite dish positioning device, but is a dandy turntable motor with quite a bit of torque and max speed of 5RPM. If powered from an HO DC transformer such as a ProTech (model Proom0001) you have not only good slow speed control, but also both momentum adjust and reverse for the bridge. The gear motor comes with a brake that needs to be removed and a large diameter mounting flange.

The problem was to connect this motor to the Bowser shaft on the Bowser Bridge. What Cary choose to do was to remove the Bowser bearing, drill a center hole slightly larger than the new Gear Motor but small enough so that the Gear motor's flange rests on the topside floor of the turntable. He placed the motor so that the Flange was visible from above. That is what I did not like. Also, he screwed the bridge to the center-rotating disk of the gear motor. What I did was create my own mounting bracket and mount the gear motor from underneath the Bowser, so that the Bowser bearing was not removed. The Bowser bridge and shaft are then connected to the gear motor by using the unused extra flange supplied with the Bowser kit.

The idea to attach the unneeded Bowser flange( supplied and attached to wood turning wheel) to the gear motor turning disk, a key aspect of this modification, was the brainchild of Dr. Milton Paige. Milt has been a friend for more than fifteen years. His great idea was to center the flange on the opening in the middle of the gear motor, so that the existing Bowser Bridge shaft could be connected thereto.

The Bowser flange was first centered on the Gear motor shaft opening. Then the Bowser flange's four screw holes were drilled and tapped into the rotating disk.

Centering on the Flange and gear motor holes was easy. By taking successively smaller brass tubes from the outer edges of the gear motor shaft hole sizing down to the size of the flange hole, the exact center was determined. Milt accomplishes this at Chicagoland Hobby where they had a number of tubes he could borrow. Bernie there, helped to determine the center, drilled and tapped the holes. After screwing in the flange, the flange was attached on the rotating disk in the exact center. But don’t screw the flange in just yet, because additional measuring will be easier of the flange is unattached.

To attach then the motor to the bottom of the Bowser turntable i created a mounting bracket consisting of a round 12” diameter 5/8” inch thick particleboard circle available from Home Depot ($1.29). (Why a circle when Cary’s thread suggest a square? Well, as an Engine rotates around on the bridge, the force on the mounting screws is not uniform with rectilinear mounts and may become reverse stressed, whereas the forces are nicely balanced with circular placed supports)

First, find the center of the particleboard circle as the intersection of the perpendicular bisectors of any two chords on the circle. Using a compass, draw a circle at a radius of the flange bolt holes; to do this, layout the gear motor flange down on the particleboard. Line up the circle with the center of the flange holes. Mark off the holes on the circle. Next, draw another circle from the particleboard center for the support holes that will attach to the underside of the turntable. This new circle should have a radius of 5”.

Next, using a hole saw, I drilled a 2-3/4” hole in the center of the particleboard circle. This hole will accommodate the rotating disk and flange. Next I drilled out the gear motor flange holes to fit a hex bolt that will be 5/16” diameter bolt (Home Depot). On one side of the particleboard circle, that will be the side facing the underside of the turntable, I countersunk the holes large enough to completely flush mount the hex head bolts. At this point I test mounted the gear motor using three hex head bolts that were 3” long (at the high point of the gear box) and two that were 2” long (at the low point). This to check if the mounting was flush.

This ends part 1, next thread continues…


Alan

[cnw1995]

Wow, this is very interesting.

[Anonymous]

Alan,

Thanks for another of your great, helpful posts. I always appreciate the thought and effort that go into your dissertations, which I study even though the subject may not be something I'm likely to tackle per se.

Folks, regardless of what forum mechanism you're on, it's best practice to save posts like this in text or HTML format on your hard drive for your personal use. Every electronic archive ever created has gotten creamed at some point in its life cycle, intentionally or no.

[Anonymous]

I just finished the Turntable Bridge see below
I added a few details over and above the ones included in the Bowser Kit:

[Anonymous]

Thanks for waiting

I just finished the detailing of the Bridge; see below; I added afew new details such as the ladder and piping to the tower.





The white wash color accents the bridge I think better than the black painted bridges I have seen; it is modeled after the UP one in the photo.

The white color also show dirt and grease a lot better; I have started to place the motor unit underneath the table and discovered I need another circular piece to attach the motor to.

to be continued...

Alan

[Buckeye Riveter]

A picture is worth a thousand words.

[Anonymous]

Done...

I mounted the motor assembly to the new table flange (another 12" particle board circle with a smaller center hole cut ) and it works. I have a few more tests to do, but it looks like a success. My motor is turning the turntable from beneath the table.

The following is a picture of the motor assembly:



Note the light pencil circle marking the position of the 1-1/4" screws that will connect to the table flange.

Also note the cutout section to give you room for your hand to tighten the set screws to the bridge shaft on the fixed collar on the motor. Additionally be sure to pass the wire that powers the center rail of the track. This is part of the Bowser Bridge beam.

The reverse siide of the motor assembly shows the fixed collar attached to the motor drive. Note the bolt heads are flush mounted on this side. I think the cutout section is shown clearer in this photo too.



This fixed collar is obtained and removed from the extra wheel that Bowser provides; I believe you can purchase these from Bowser seperately. Check with them!

The next step is to secure the table flange under the table. I aligned the small center hole with the cut-out in an easily accessable position. Tthen I attached the motor assembly over the table flange making sure the cutoff section align (remember not to squeeze the enter rail wire between the two flanges too. )

The motor assembly fixed collar is already centered so you just place and align the hole in the fixed collar over the bridge shaft. There is no missing or repositioning or shifting because the SHAFT and COLLAR easily align.

Once in place I screwed in the circular-placed screws of the motor assembly cflange into the table flange; Next I tightend the set screws on the fixed collar; wire the motor to a transformer.


to be continued.....

[Anonymous]

An excellent description! Too darned bad All Electronics no longer has these motors available.

I wonder if some sort of a toothed belt reduction drive using a higher RPM gear motor can be developed for this beautiful turmtable?

Tony

[Pennvalley]

Try this supplier.

http://www.surpluscenter.com/item.asp?UID=2003101723335152&item=5-1440&catname=electric

[Anonymous]

The motor was originally about $35 now it is about $17; I thought it was available too. That site above is the puppy for $19... only 2800 left …so better get one soon if you are thinking about a turntable. or maybe buy two!!

You can thank the di***V industry for making upgrades to their systems that don't require rotating antennas as much... so there are a lot of surplus motors.

The Bowser Turntable is not a "high" craftsman project. But the results are really good for an easy to build project. Good thing because I like to think of myself as a "commercial" modeler. I do most of my train work during TV commercials. It makes me think several steps ahead so that I can have all the tools and supplies ready and then can do this or that in a short time.


I will be posting photos of the bridge walkway that I planked; I then lightly sanded the top to create a wear-down look and spotted the top with India ink/water to create dirty spots. I spotted the bottom of the girders too.

Alan

[Anonymous]

CONCLUDING

Before installation of the table flange you’ll note the shaft peaking thru. This shaft is connected to the turntable bridge;



When last I described the turntable motor I had yet to provide photos of the secondary or table flange that was first attached to the turntable:



the above photo shows the table flange just before installation; I applied plywood glue to the face that will attach to the underside of the table; The next photo



shows the screws pre-drilled on the other side; the ring of screws were placed so that the screws and bolts of the motor flange would not interfere. The photo shows the moter flange with the screws pre-drilled and screwed in partway.



I centered the larger hole around the shaft and screwed-away, thus attaching the table flange; next I placed the motor assembly and its flange over the table flange; aligning the collar over the shaft. The was then screwed into the table flange see photo



the two flanges are pancaked together; you need to keep the black wire that come from the turntable bridge center rail clear, so it can be attached to power later.
At this point I tightened the screws in the collar to the shaft. The motor power lines are connected to a standard DC power supply- I used the Ultra HO Train Power Pack from PROTECH because it has a momentum control to control my turntable motor.


To install the lines around the turntable I use a laser level from Sears, but before I did that I installed a curb around the turntable. The curbing gives a better finish look to the turntable where my roadbed ends. I will discuss these in a later thread. Look close in the photo below see the RED laser line that helped line up the roadbed to site the loaction. I used this for each line in and out.



Alan

[Anonymous]

added new photos above

Alan

[CSX FAN]

Alan

Great idea, looks very strong but i have one question. How will you index the stop points? Or do you do it manualy?

Jamie

[Anonymous]

Jamie

the beauty of this dish-antenna motor is that it moves so slowly and locks in place when it stops that an indexing system is not needed. I use the momentum control on the transformer to easily glide the bridge into place.

By the way I have some more details on turntable track locations on my crossover thread

http://www.trains.com/community/forum/topic.asp?TOPIC_ID=14992


Alan

[Anonymous]

Indexing

Several people has asked about an indexing method. Although I really don't think it is necessary due to the slow speed of the motor, an indexing system is possible.

By attaching a strong magnet to the bottom of the bridge on top and close to the bottom of the pit , you could then attach magnetic reed switches (radio shack) to the underside of the pit at positions corresponding to the stop points above. As the bridge moves the magnet could trigger the reed switches that could then trigger a relay to interrupt the power to the motor.

To move to the next line, an override switch could then short the reed switch providing power to the motor. But again I dont think that is necessary because the motor moves very slowly.

Alan

[CSX FAN]

Alan

Do you think a fly wheel could be added so I could use a Dalee index kit?

Jamie

[Anonymous]

This being York week, I've been thinking about Cary quite a bit. It's been over 2 years already since he passed away. I've got the original Turntable Article at home if anyone is interested. You can email me at: [e-mail] if you would like more info.

Here's a link in Cary's Memory: http://sages.us/rumkeweb/Cary%20Memories.htm

[FJ and G]

Alan,

Great info.

Agree w/Rick. Don't assume stuff on the Internet is forever, despite what OGR or others might claim (when they went over to their new server I asked if stuff would be deleted and Rich said "no."). I'm sure they didn't intend to delete anything. But with servers and other IT stuff, the old saying that stuff happens applies.

[Pennvalley]

Can't find that motor setup, guess all the o gauge guys bought them up.[:D]