I am busy converting my Optimum BF20L Vario mill to CNC. I have finished the ball-screws and the other mechanical changes. I have done a lot of reading about the connections of the stepper motors for the X, Y and Z axis to their controllers and don't see much problems with those. My problem is that I cannot find clear details of how I must connect the variable speed control board of the spindle to the breakout board. Any help on this would help, especially if you have pictures of the connections on the BF20L's board. Any suggestions is also welcome. Thanks.