hello, i am getting into casting because there are specific unique parts i must make, some of these parts need to have threads in them so i can screw them to plastic resin parts. if anyone knows how to do that, or if it can be done, please let me know? i dont know if that is possible in the casting stages or will have to have a machinist put it in or can i do that myself without a metal lathe? i do have a drill press.. thanks.