Dear Metalworking Toolmakers: you are wrong about taps. (and so was I - mostly because of you)

 First, let me explain.  No, there is too much.  Let me sum up.

 I am making two handles which require a very deep (≈1.5in) threaded (10-32) hole.  The material is some unknown high strength aluminum.  One of the ways I have broken taps in the past is tapping holes not even that deep, although that was also a smaller hole/thread, so I am slightly charry about this task.

 So I go looking for the deep-thread-making kinda tap, which I thought, due to a variety of sources, was called a "plug tap".  Bzzt, wrong!  Searching for same constantly turned up taps close to what I was looking for, but the results were spotty.

 So it turns out, "plug" refers only to the taper on the end of the tap.  While it is quite common for extra-long taps to have a plug taper on the end, it does not define or name the overall tap; just that taper.

 Extra-long taps, which I am seeking, come in two varieties; Extension taps, and Pulley taps.

 Extension taps have a shank which is smaller than the thread-cutting part, so the shank itself can pass into the threaded hole the tap is making. The downside is that the shank is much smaller and therefore easier to break.

 Pulley taps have a larger shank, making the shank less likely to break.  They are designed for tasks like pulley hubs, where the threaded depth is unlikely to be greater than the thread length of the tap.

 That's it, that's the only difference between those two; shank size relative to the thread's major diameter.

 And while the plug taper is the most common taper found on long taps, they can have any taper, any number of flutes, any of a variety of coatings, and so on.

 So, manufacturers and resellers: fix yer damn web stores. 😛