Starrett Spindle Square How-To-Use
After setting the spindle square indicators to "0" on a surface plate, place the Starrett Spindle Square into the collet of the milling machine and bring the head down to the table until both indicator needles have rotated approximately one full rotation. The needles do not need to point in the same direction. Identical numerical readings, not the needle positions, indicate squareness. To tram the milling machine, adjust the machine per normal procedures until both indicators read the same numerical value. After setting the X-axis, repeat the same procedure with the Y-axis.