A 3D Printing Project

In this post, I stated that the 3D Printer was once again fired up and running. Now I have the “good” kind of problem that presents itself while stumbling around Thingiverse: I found a big project I want to build!

I decided to print this 100 foot N-scale turntable. It’s one of those things you would see in a large yard with an engine roundhouse. Would I love to build a large yard, someday, maybe, but having a way to turn engines on small layout is fun and practical as well. The designer on Thingiverse has an entire webpage dedicated to how he built this design, including wiring and writing some code to automate the table.

For now, I’m thinking this will be a static display. The table will turn, and I will wire it for power, but as a standalone module, with the option of adding it as an extension to the layout at some point. Aside from the 3-D printing, painting, assembly and wiring, I’m thinking this might be an automation project to boot!

Here are the parts I’ve printed thus far. On the chipboard you can see the bridge, the two center parts that hold the track to the top of the bridge and finish the decking. There are two platform extensions, that glue to the sides of the center bits. Both have a center platform that will have pit ladders attached (those will be added later. I printed two center planking strips (one narrow one wide) and they will fit between the tracks to cover some sins and give the top deck a finished look.

The big ring is a single track that sits down in the pit and what the real life bridge would rotate upon. This bit will cover the connection point between the yet to be printed floor and wall.

Lastly, there are the two parts that make up the operators house. You can see where it will sit on the top extension in the photo.


The prints aren’t injection molded smooth, but I think they will work well enough. I’ve still got the pit floor, pit walls and the unseen support disk to print, they are all 12+ hour prints, so I decided to start the little bit of scratch building that is required.

The design requires some small rods at the four corners of the bridge, I didn’t have any 0.04″ styrene rods, but I did have some 3/64 rods, and that was close enough (that would be 0.046″ for you decimal-headed metric system folks!). I am grateful that the designer left this for dimentional styrene, as I don’t think these would have printed well at all. I think the side plate junctions on the bridge could have been made from square stock, but I think with some minor clean-up and paint they’ll look fine.

I also cut the window frame from the Operator’s House, they didn’t print well, and replaced them with some 0.040″ square styrene beams, once primed and painted they should look the part.

Later I’ll need to find some rolling stock trucks and remove the four wheels, they will act as guide wheels for when the bridge section spins. And to spin it I’ll need to gather a stepper motor, a slip ring and a motor controller. Searching YouTube today I found a-hundred-and-one ways to make that happen, so that decision on methodology and how complicated I want to go is for my future self to figure out!

I still need to get some regular track long enough to fit the length of the bridge, as the Kato Unitrack has an integrated road bed that wouldn’t look the part, why lay ballast when you have the rails firmly attached to a steel girder-plate bridge? This really isn’t a problem as Atlas flex-track is pretty cheap and available at most hobby shops – no special orders, just chop off the needed length, a little sanding of the plastic ties and then I can start assembling all the bits.

This project will require me to pick up a soldering iron and the bits that go with that, but I would need one eventually with the layout itself. I’m thinking that item can wait until after the holidays or maybe if I see one go on sale…

Anyway, this is just the beginning and I’ll try to update things as the move along.


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