Model railroading is a serious hobby for its enthusiasts. People who are involved in model railroading build elaborate displays based on geographic area or periods in history. The goal of a layout like this is to take reality, and scale it down to a miniature world. This world contains trains built and painted like their real-life counterparts, buildings, vehicles, people, even trees and mountains. One accessory you can add to a layout is a turntable. Turntables were used in the steam era to turn locomotives around when they were at the end of the line, as they couldn't efficiently be run in reverse.
Determine how big the turntable will need to be. In most cases, if you have an O-scale layout, it should be at least 15 inches; HO should be at least 10 inches; and N scale should be at least 6 inches.Decide where in your layout you will put the turntable.
It will have to be in an area where there are no support beams or other obstructions underneath the area, and also have enough room for a roundhouse if you are adding one to your layout. (A roundhouse is the building where maintenance work is done on locomotives.)Draw a square box at least 4 inches longer than the length of the turntable bridge on the surface of the plywood sub-roadbed with a carpenter's square (the sub-roadbed is the plywood upon which your display is built).Draw diagonal lines that intersect at the exact center of the square.Use a compass to draw a circle inside the square, using the center of the square as the pivot point.Drill small holes at each corner of the square, as well as in the center, using a drill bit that's 1/16 inch or smaller.
Build Workbench In Shed
These holes will act as guides when you're working underneath the table.Cut a square of 1/4-inch plywood the same size as the square you drew in Step 3. This will be the floor of the turntable pit.Using the guide holes, drill four mounting holes in the floor piece. Attach the floor underneath the sub-roadbed with mounting screws and mark a corner of the floor and the sub-roadbed with an X.Remove the pit floor, then cut the square out of the sub-roadbed with a jigsaw or saber saw. Cut the circle out of the piece at a workbench.Re-attach the pit floor to the bottom of the sub-roadbed and trace around the opening where the pit wall and floor meet.