How do you run a double-lead tap?
As you probably already know, a double-lead tap traverses twice the distance per rotation as a standard tap would. The question of how to run them comes up from time to time, so we thought this would be a good entry for the technical section of our speeds and feeds blog.
The feed rate will be twice that of a regular tap, so to compensate, cut the RPM that you are running at to about 1/2 of what you would run a single lead tap at.
http://www.kodiakcuttingtools.com/viewproducts/double-lead-taps