Cincinnati Magnum 800 Spindle Repair

Cincinnati Milacron Magnum 800 Spindle Repair

The Cincinnati Milacron Magnum 800 is a horizontal machining center equipped with a 50 HP spindle running up to 6,500 rpm with a CAT 50 tool holder.

Cincinnati Milacron Magnum 800 Spindle Repair


Our customer experienced a crash with their machine, causing damage to the interior of the spindle, as well as where it made contact with the workpiece.
[caption id="attachment_4288" align="aligncenter" width="300"]Cincinnati Milacron Magnum 800 Spindle Repair Incoming spindle from customer[/caption]
Dimensional analysis revealed that critical components were out of spec. The tooling taper ID measured with severe runout of >50µ. The #2 bearing had started to weld to the shaft, which caused the surface to become uneven and resulted in damage to all of the journals as it was pressed off the length of the shaft.
[caption id="attachment_4289" align="aligncenter" width="300"]Cincinnati Milacron Magnum 800 Spindle Repair Breakdown and inspection[/caption]
All of the interior bearings had become severely contaminated with black sludge - a mixture of lubricant, coolant, and material swarf. The gear began to heavily fret on the shaft causing a significant difference of >70µ clearance.


All components were thoroughly cleaned and refurbished. This repair required a full replacement of new bearings, bolts, o-rings and seal, and Belleville washers, and a gear was sent to a requalifying facility to be refurbished. This repair required significant precision grinding work to bring critical dimensions back to OEM spec. A grind-chrome plate-finish grind process was performed on the three 100mm bearing journals, CAT50 ID taper, and the 90mm surface where the gear is located on the shaft. Additional light grinding was performed on the shaft nose OD to address minor cosmetic damage.
[caption id="attachment_4287" align="alignleft" width="300"]Cincinnati Milicron Magnum 800 Spindle Repair Bearing journals and shoulder after application of chrome-plating[/caption]


After performing all dimensional work, the spindle entered the final stages of our repair process:
  • Adjust bearing preload
  • Reassemble entire spindle
  • Balance shaft
  • Break-in procedure
  • Pass quality control inspection
Every Northland Tool repair is backed by a 1-year warranty.

Cincinnati Magnum 800 Spindle Repair


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More Case Studies

Repair History - Here are examples of similar spindle repairs that may contain additional information that will help you. If you have additional questions, please contact us.