If you are using the hole tool, use the thread tool after you create the
hole and you will be able to add the NPT threads (the threads and the hole
will be separate features). If you are extruding a circle in a sketch to
create the hole, add a face angle to the hole and the NPT threads will be
selected by default when you use the thread tool.
--
Hal Gwin
Mechanical Designer
Xenogen