Forest Line Spindle Repair

The robust style of the Forest Line machines and a small installation base doesn’t lend to a huge volume of Forest Line spindle repair for Northland Tool & Electronics but when we get them we do it right. We have the equipment and the expertise to rebuild the larger style milling spindles. We have helped our customers with contamination prevention and getting their machine up and running in a short time frame.


We received a Forest Line milling spindle attachment that the customer had been rebuilding themselves quite often over the past few years. The bearing dimensions were worn to the point that the bearings fell off the shaft during the disassembly process. The customer complained that even after they installed new bearings in the spindle it was making noise and unable to hold tolerance.

In addition to the shaft bearing journals being far undersized we also discovered that the taper had 15 microns runout, the shaft journals had 20 microns runout, the front and rear housings were egged, and the grippers were damaged.

Parts for this spindle were not available from the OEM so Northland Tool & Electronic’s machining and grinding departments were called upon to manufacture a variety of the parts that were needed.



The following actions were performed on this Forest Line spindle:

  • Clean all parts of the spindle
  • Replace all bolts and o-rings
  • Replace bearings
  • Replace grippers
  • Grind, chrome plate, and finish grind (GPG) the taper and journals.
  • GPG the front and rear housings
  • GPG the drive shaft and gear housing
  • Kiss grind the bearing shoulders



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.


  • Forest Line Spindle Repair

  • Forest Line Spindle Repair

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