is the class of thread required to be close ? if its not critical, i'd over size the hole a few thousands and then, using a good gun tap, start each hole with the tap in the mill, keeping it straight, then finish the hole by hand. cutting oil will be your friend.
that's a bunch of holes even at that. . . your hands will be swearing at you. . .
actually, my RF30 hardly coasts long enough to even turn it off at the same time the tap would enter the material.
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is the class of thread required to be close ? if its not critical, i'd over size the hole a few thousands and then, using a good gun tap, start each hole with the tap in the mill, keeping it straight, then finish the hole by hand. cutting oil will be your friend.
that's a bunch of holes even at that. . . your hands will be swearing at you. . .
actually, my RF30 hardly coasts long enough to even turn it off at the same time the tap would enter the material.