[CR]tap and die sets?

With all this talk of Campagnolo crankset failures, I'm reminded that I need to chase the threads in my crank arms as well as clean up the threads on two sets of Campagnolo pedals.

So, silly me, I Googled Tap & Die sets. Lots of sets, nothing 9/16 x 20.

The closest thing I can find are rethread kits (sounds right to me) on the Snap On site.

http://buy1.snapon.com/catalog/catalog1.asp?tool=all&Cat_ID=2224547&Cat_NAME=Thread+Restoring&store=snapon-store

Any ideas for specific products? Any particular reason why everything kind of stops at 9/16 x 18 and skips 9/16 x 20?

Ann Phillips,
Decatur GA