Detail Photos of the Turntable
Bernd had asked to me to post a few photos of the turntable drive, so I've added some images below. But first I'll make a few comments regarding my first impressions of the kit.
The kit components are kind of a good news/bad news thing. Two of the parts sprues are warped, one severely, that one being the sprue with the bridge tie assembly and the handrails. Later when I cut the parts loose I'll have to determine whether they can be glued sufficiently to the main bridge to force them into alignment. The other warped sprue contains mostly smaller parts plus the large driven gear. Fortunately, the individual parts seem to be okay.
The pit is it's own separate molding and it seems to be quite straight and true. I placed it upside down on a flat surface and didn't notice any gaps around the perimeter. I also fit the bridge structure into the pit and it easily clears the pit walls all the way around so I don't think there is any significant warpage of the walls.
I was quite surprised that the bridge structure itself is molded as one big solid piece with an integral center shaft. The only assembly required is gluing on the aforementioned bridge tie molding, the railings, rails and various detailing parts.
On to the photos . . .
Here is the one-piece bridge sitting in the pit (obviously no detail or track structure added). Painting the pit and the pit rail/ties looks like it will be a challenge.
This is the underside with the bearings, spacers, driven gear, and slip rings in place. The cover is on the right. If you were to power the turntable with the accessory drive motor, it would mount in the rectangular corner space at the top left of the cover. The drive is sealed in a plastic box with the edge of the drive gear exposed. When the box is screwed into the cover, the drive gear will mesh with the large gear under the pit once the cover is installed. There seems to be no way to adjust for gear lash, or even to inspect the mesh once the motor assembly/cover are screwed into place on the pit bottom. The hole in the bottom center of the cover receives the bottom sleeve bearing for the center shaft. There is also a plastic piece that two bronze wipers are attached to (not shown). It attaches into the bottom cover and also slips into the "slot" seen on the pit bottom between the two screw bosses. The wipers are supposed to be bent such that they bear against the wiper rings. To prepare the rings, you must solder a wire to the inside of each ring, and route the wires through a slot in the center shaft (which is hollow) and up to the bridge. The wires are to be soldered to the bottom of the rails, then the rails glued to the tie structure. Below, wires are to be attached to the wipers and then routed out for connection to the track bus for power.
And here is the bottom cover in place.
This shows the individual parts that are assembled to the bridge center shaft. At the far left is the upper plastic sleeve bearing (inserted from the top of the pit). The bridge is then inserted from the top and the remainder of the components slide onto the center shaft from the bottom. From left to right, they are: metal washer, large driven gear, brass wiper ring, plastic spacer, another brass wiper ring, bottom plastic sleeve bearing.
When the cover at right is placed onto the pit bottom, the bridge center shaft and bottom sleeve bearing will insert into the depression seen in the center of the cover. There is some slop in the entire bridge assembly once all together. But the bridge does rotate very easily and despite having done no clean-up of the parts and no lubrication, the bridge spun around without any signs of binding, or "jumping". Of course the bridge will later have the support structures with rollers, one at each end of the bridge. Hopefully they won't create a bind or other unwanted condition.
So, preliminary indications are that the turntable will do a satisfactory job using "finger power" to spin the bridge. I am disappointed though that the cover must be in place in order to support the bottom of the bridge shaft. That would seem to complicate efforts to design a home-made drive mechanism.
-Jack