Building a seesaw with sliding seats
Instructions - the beam
Step 4. Prepare the beam
Drill a hole in the center of the beam [d] close to the bottom. Note that the beam is upside-down in the photos.
Make the hole size big enough to take a piece of pipe or tube that has an inside diameter of 1/2" (12mm). Obviously the overall, outside pipe diameter will be bigger than the inside diameter.
Stick the pipe or tube into the hole and cut it flush at each end.
Glue and screw piece [d2] to the beam [d] as shown in the pictures.
Cover the hole (one side only) with a piece of 3x3 (75mm x 75mm) galvanized tie plate.
Drill a 1/2" (12mm) hole through the tie plate, where the pipe is. You will have to drill from the other side, through the pipe and then the plate.
Cover the other end of the hole with a similar piece of galvanized tie plate and repeat the drilling procedure.