Setting up a DIY Aluminium Foundry and wanted a really "premo" means for connecting the Hair Dryer to the 1" threaded steel pipe. Most hair dryers have an oval output port. The one the Wife gave me (great excuse to get a new one!) has an oval of 48 mm x 58 mm and the 1" pipe is standard that you find at any hardware store.
For those that are not versed in what this is for... You use a hair dryer's blower to blow air into the charcoal to super heat and melt the aluminium. See youtube video
I'm not the creator of this video. I learned from it myself. :)
The internal threads are 11/per inch with a pitch of .08696" which comes from the national standard pipe thread NPT charts.