Yes, 14.6 diam for going in to 15mm, if it is too loose you could always redesign for 14.7 or 14.8. With threading make sure the threads are pretty big so the print has enough resolution for them to be worthwhile, and as threads will mate together you might even still get a fairly tight fit for having a <14.6mm diam. There might well be, specifically for threaded parts, some sort of "thread calibration" models on the likes of hingiverse or printables, which you can use to get a feel for how different thread sizes and tolerances would come out from your printer.