Quote Originally Posted by m_c View Post
Where the cutting edge is, and what direction the material has to turn in relation to the cutting edge. The turret on my lathe is rear mounted with the disc machined so 12mm tools have their cutting edge level and facing down when at the spindle (click the pic if you want to see a vid of it changing position a couple times)
Sorry, my question was unclear.

I understand when I need CW and when CCW. What 'setting' tells the spindle to rotate CW or CCW depending on the tool choice?