YG-1 G0 Series Vanadium Alloy HSS Spiral Flute Tap, Uncoated (Bright) Finish, Round Shank with Square End, Modified Bottoming Chamfer, #4-40 Thread Size, H2 Tolerance

This 4-40 spiral flute really is great!Ive used it on aluminum and ABS with great results.Often I just chuck it up in a cordless drill and haven't broken it yet.Works just as well in a tap wrench or the tail stock of my mini lathe.I can definitely recommend them.One word of caution, I had to buy these because I dropped the first one in a pike of chips and never saw it again!They're easy to loose.

I primarily ran this in my Haas VMC tapping 6061 aluminium anywhere between 1/8 deep upwards of a half inch deep.In that machine I had tapped close to 18k holes and close to 2k in a hand drill / tapping arm in other setups. It only broke because of user errorThat's 0.0004 cents per hole.