The "This site" link is awesome.

Please note: The inside diameter for the instrument they diagram/blueprint will require that you purchase PVC Schedule 40 pipe. PVC pipe is sold based on its outside diameter, and if memory serves me, that means you should ask for 1" pipe. However, it has to be Schedule 40--Schedule 80 would have a more restricted ID. (I worked in a PVC pipe manufacturing plant about 25 years ago.)

PVC stands for polyvinyl chloride. I would suggest that you bevel the end that is going to be inserted into the fitting. Not too much; just enough to take the sharp end off the piece of pipe. A handsaw will cut the pipe quite conveniently.

The pipe shold friction fit with the coupling. If you put it on permanently using the solvent cement sold for that purpose, make the fit and hold it for about 30 seconds when the cement is 'drying'. Otherwise, the coupling and pipe will have a tendency to want to separate a bit, and the finished product will suffer in appearance.

Domo arigato, Masato. I learned something new today.

PS PVC pipe used to be sold in 20' lengths. See if a plumber or hardware store will cut to the length you want. Otherwise, you are gonna end up with one long instrument that will be a real bear getting into a car.