Hardinge Bridgeport XV 710 Spindle Repair

The Hardinge Bridgeport XV 710 is a CNC vertical machining center.  It comes equipped with a grease lubricated and belt driven spindle capable of running up to 8,000 rpm.

CHALLENGE

When this Hardinge Bridgeport XV 710 spindle arrived at our facility, the first thing we noticed was that the bearings were noisy when rotated by hand in assembly.  During disassembly, we noted that the gripper assembly was not tightened to the drawbar and some bellevilles were broken.  After fully evaluating the spindle, it was found that the gripper fingers had significant wear on critical holding surfaces and the tooling taper ID had considerable damage.  It appeared that a tool had spun in it.  We also noted that both the front and rear bearing pairs contained excessive grease and the grease in the front pair was contaminated.  No other significant dimensional deviations were noted on any critical surfaces(bearing journals/shoulders, housing bores.)

SOLUTION

The following actions were performed on this Hardinge Bridgeport XV 710 spindle:

• Clean, inspect overall dimensions
• Grind, chrome plate, and finish grind the tooling taper ID
• Replace all bearings, bellevilles, grippers, o-rings, and assembly screws

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.