Originally Posted by
jefilomeno
Also, I know this sounds crazy, but I have actually reamed a dead on hole size in non ferrous materials with a spiral flute bottom tap, in a rigid collet chuck feeding at a slow feed. The teeth on th tap act like a bunch of very precision cutting edges. Works great in aluminum. Nice finish to.
And when you discovered this little tidbit, were you intending to ream the hole or thread the hole?
It does sound like a heck of an idea, better than using an endmill, because the upper body of a tap is not relieved, so it will burnish the hole, yet the contact is minimal, and coolant flow should be good.
Plus, the rake angle of the spiral flute will give a nice positive cutting action compared to the dumb scraping of a straight flute machine reamer.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)