The 3.175mm is 1/8 inch, I'm assuming the 13mm is close enough for a 1/2 inch shank but a 1/4 inch shank would be 6.35mm. The price point is very good for that spindle, but for cuemaking I think 2.2K is overkill. I run a 1050 Kress on one of my machines and it has plenty of power, although on...