Hi Marvin,
This reply may be a little late. I make many trumpet calls. I find that drilling (boring) the holes for your calls may wander, I have found doing them on the lathe helps and be sure to drill very slowly. I also drill a 1/4" hole at the exit end on the blank after the other holes have been completed, for your mouth piece. I got a tapered reamer from Lee Valley Tools, it Is made for making tapered holes for making chairs ($30 can) , it is about 4" long and works great. I also make my own mouth pieces using Delrin Rod , this may take you time to practice, carbide tools , 1500 RPM , when dilling 3/16" hole go slow and never drill to far each time , delrin heats easily and will seize bit if you don't clear material.
Hope this will help
Wayne Howard