Pecos NB-55 turntable is a great item for us that is running N-scale. Easy to fit into the layout and a ok price compared to for example Fleishmann’s 9152c turntable. But it also has its problems. There is no easy and cheap way to make the turntable driven by a motor. Sure, in the instructions there is a picture with some Mechano parts, but far from ready and still controlled by hand. So I decided to build my own motor controlled NB-55 turntable. This is how I did it
First of all, we need to fix the axle into the center piece of the turntable. We need to do this now before we assemble it as it’s pretty tricky to drill holes after we glued everything together. The axle need to be 4mm in diameter. I used a brass one that I had lying around. Glue together the two parts where the axle will fit. Once it’s dried, put in the brass axle and drill a 1 mm hole thru the plastic, the brass axle and the plastic again. This will make sure that the axle don’t rotate in the holder without moving the turntable bridge. Thru the hole, I placed a 1 mm brass axle.
Once that is done, assembly the rest of the bridge. I skipped the railings at this stage as they were just annoying to have mounted when I worked with the bridge up-side-down.
When everything is dried, we need to mount a couple of railroad wheels, as the original design sucks when it comes to this part. Plastic against plastic after it’s painted and weathered is not something I could recommend. I took mine from an old wagon that I don’t use anymore. The distances I specify here worked for my 8mm in diameter wheel. If you have a smaller or larger wheel, you need to adjust these.
On my wheels, the flange where too big so I had to remove a couple of mm. The wheel on one side of the wheel axle was left with a 1 to 1.5 mm flange and on the other wheel on the same axle I removed the flange all together. You could also remove that wheel but mine was just sitting to hard so I left it there. The wheel with the flange will go on the plastic rail in the turntable, and the other wheel have no function at all.
Before we start to assemble the wheel construction, there are two small-small lines under the bridge that you need to cut off with a knife. Look at the markings on the picture to see what I mean here.
I used plastic card to do my construction. Cut four pieces of a 0,75×6.3 mm plastic card so they are long enough to just fit between the two sides on the turntable bridge. Also cut 4 pieces of 2×2 mm plastic card to stabilize the larger parts. If you have thicker cards of the 6.3 mm wide ones, you might not need the 2×2 mm. I took what I had home. The parts I used came from Evergreen and they have part number 139 and 164.
Drill a 0.7 mm hole in the 0,75×6.3mm part, that is just centered in the middle and 4.8 mm up from the edge. This is where the wheels will be. Glue the 2×2 mm part to the side that is on the opposite side compared to the 0.7mm hole. Do this on all 4 parts. Once the glue is dry, we are ready to mount them on the turntable bridge. Measure an extra time here so the wheels come in the right position over the plastic rail in the turntable. The bridge and turntable is now complete and we can continue with the motor.
I bought a motor out of eBay that have a gearbox and will do 3rpm with 12V. The one I found had a 6-mm axle, so I also ordered a shaft coupling for a 4/6 mm axle. Total price for these two where 16$. The motor has 4 holes in the gearbox, and I used them to screw the motor and gearbox on to a 1.5mm thick aluminum board. This board where then fixed under the turntable with the help of two small wooden pieces. Once motor is in place it’s time to cut the brass axle so it fits into the shaft coupler. And then you are done. Try to connect some power to you motor and the turntable should turn.