FRETS.COM
Shop Tip #351
© Frank Ford 2006; Photo by FF

Don't buy "carbon steel" taps from your local hardware store or anywhere else.  Instead, get "high speed steel" ones from a machine tool supplier.  They won't cost you more, and they are WAY worth the effort. They cut better, last longer, and are harder to break.  I especially like the "spiral point" taps like the one on the left.