Wow! What a question. First Brian;s answer is correct. Buy quality. the next is your context. Taps for airguns has no meaning. The real question is what kind of investment are you prepared to make? I have thousands invested in taps of all flavors. Are you prepared for the cost of complete sets in multiple families? If not, identify the exact sizes and flavor and buy only those. That would not be my solution, but if only a few sizes are needed, perhaps that;s the best for you. Keep in mind that taps and dies are a consumable. They break, and they wear out.under use. Please also note that in most cases an individual thread size will require 3 different tap styles.and these styles come in European systems and American systems. The European system is progressive in that each tap cuts a bit deeper reducing the tap load. The American system uses different start tapers, but all 3 taps in a set will cut full depth at the end.. Depending on the air gun, the thread family may be Metric or SAE. In those cases the thread form is an included angle of 60 degrees. Most high pressure fittings will be British BSPP or BSPT (British Standard Pipe Parallel or Tapered), These thread families use a 55 degree thread form, Again, there are exceptions to everything and some high pressure fittings are NPT (National Pipe Tapered (60 degree thread form)). The standard taper for all tapered pipes is 3/4" per foot and when tapping, you should use a tapered reamer first to establish the taper before threading. Please also note that threads are identified by major diameter and then pitch. The American method of pitch is the number threads per inch of travel. The Metric method is distance traveled in mm per revolution. Of course pipe is the exception where the specified diameter is of the typical internal diameter of the pipe. One more additional note, all tapered pipe threads seal on the thread. All parallel pipe threads seal on a separate internal or external seal, not on the threads. I apologize for being a bit verbose, but your query indicated a lack of thread knowledge. The subject is a lot more complex than the brief description above, but Google is your friend.
