Just for info / knowledge or maybe its because I'm an anorak but thats a taper tap, which is used to initially start the threaded hole. Ideally that should be followed by a second and finally a plug or bottoming tap which would be essential if the hole in the metal was blind.
All screw cutting taps like this one need the correct size of tapping drill before the thread will be formed correctly, and a suitable cutting lubricant is essential.....not to mention the technique!
Anyone remember the Zeus booklet for tapping sizes, and Trefolex cutting grease?
John