1.4 P4 angular contact bearings , 2×7005C P4 DT &2×7003C P4 DT,increase spindle life. (4 pcs P4 bearings)
2.Can be rotated front cover,water difficult into spindle,increase spindle life.
3.Longer length make the torque bigger,more powerful.
4.Carefull assembly make the spindle more precisional.
5.Runout off 0.01mm.Coaxial degree less than 0.0025mm.