I have made about a dozen various sized turkey pot calls, it takes a little trial and error to get the proper amount of wood removed from the wood "pot" depending on the type of wood used to get the desired sound from the call. I was having good luck using some Tiger wood which is a heavy and dense wood that looks good when turned. You also need to determine what kind of sound board material to use for the call, slate is available in a variety of sizes and provides for a traditional sounding call. There are other materials being used these days to provide different tones of sound that some of the birds seem to be interested in when they get used to the slate calls. Copper, glass, ceramic and aluminum is being used by some of the call makers to provide for different tones. The better quality calls usually use a larger striking surface on top and a smaller sound board directly below the striking surface with small air gap between them. Some of the calls have a small hole on the bottom side that allows striking the sound board to produce a different tone.
You can also use a carbon fiber arrow shaft to make a high quality strikers with or you can make a traditional striker out of various hard woods. When making a striker out of a carbon fiber shaft, you cut and glue the shaft into a wood handle and then cut the shaft or turn wood off of the handle to get the right kind of sound from the striker.
There are a number of YouTube videos that cover the basic process of turning a pot call on the wood lathe.