Kitamura Mycenter HX1000i Rear roller failure


Kitamura Mycenter HX1000i, 8,000 RPM, oil mist lubrication, gear driven

Rear roller failure damaged the housing bore, flaking chrome in Big-Plus 50 taper

This spindle arrived at our facility seized because of a catastrophic failure of the rear roller bearing. When the cage that normally contains the rollers disintegrated, the crushed phenolic material migrated to the front of the spindle, contaminating the ceramic quad set. Another result of the rear roller failure was that several deep grooves were created in the rear housing bore as the destroyed bearing rotated. We also observed that the Big-Plus dual-contact tooling 50 taper ID was damaged, and that the face was worn down as well. In addition, we noted that the taper ID had been previously plated, and that the hard chrome was flaking where the ID had taken some hits.



We performed a precision grind, chrome plate & finish grind of the rear housing bore to remedy the damage from the bearing failure. We also did a grind/plate/grind of the 50 taper ID & kiss ground the face of the shaft to preserve the Big-Plus dual-contact functionality. When all components had been thoroughly cleaned, we reassembled the spindle with new bearings, setting the proper preload, and replaced the o-rings and assembly screws. Our final QC process included run up of the spindle with vibration & thermal analysis during the three hour test run. Unfortunately, we could not check tool retention force or trim balance the spindle because our customer was unable to provide us with the drawbar assembly, drive dogs & keyed drive gear.


  • Debris on the interior of the spindle from the failed bearing

  • Chrome flaking in the taper

  • Scoring in the rear housing from the failed rear bearing spinning in the housing

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I really didn’t expect this; You guys really pulled it off! My many thanks to Sandy, Louis and your outstanding crew for helping us get back into production.

Dan Eaton, Taylor Metalworks

Lou all in all everything is running good. Just had a call from Sandy just the other day, its funny great minds think alike. Its great not to be sending spindles out on a regular basis since you addressed my problems, but I know they will still be coming sooner or later. Never a problem when we get them back , run better than new. Hope everything is ok there. Please tell everyone there that we here appreciate everything that you do to keep us up and running and the quick turnarounds. Have delt with the rest now deal with the best. Have a great week end and up and coming holiday.

Northland Customer

Thank you Debbie just received spindle today and WOW ! what a nice job. Can’t wait to use it. Thank the Northland team for us for a job well done 

Northland Customer

Both of the spindles that you repaired are on the machines and running great. We don’t have any spares for those grinders. We probably will not be purchasing a spare, as you have been able to turn around the repairs quickly and the price of a spare is cost prohibitive.

Northland Customer

I am writing to thank Northland Tool for going the extra mile and saving my company from expensive machine downtime and expensive repairs. We have always sent our Chiron spindles for repair as a shaft with bearings. None of our previous rebuilders pointed out the bearing fretting or the fact that the housing in the machine was out of tolerance and causing premature failure to the spindles. After Northland fixed the housings the spindles have never sounded as good or run as well! Great job guys!

Northland Customer

The detailed cause of failure reports and the expert technical advice that Northland Tool provides is bar none the best I have ever seen. We struggled to keep two of our large our milling spindles running for longer than 6 to 12 months. Northland Tools evaluation showed that the hydraulic nuts were not holding the assembly together causing premature spindle failure. We discussed this in detail and mutually decided to modify the spindle shaft to prevent this from occurring again. The first spindle we performed this on is still in the machine running like new after 3 years. That’s over three times the life of previous repairs and it’s still going strong. Easily over $40,000.00 of savings so far on that one machine and counting.

Northland Customer

Your people go above and beyond the call of duty when it comes to spindle repair. When we had difficulty with the spindle installation and we were able to talk directly to a spindle technician that helped us troubleshoot the issue it helped us out of a bind. We have sent several spindles to you and have nothing but great things to say.

Northland Customer

Thank you for your attention with my quick turn spindle repair. Your status updates allowed me to plan around machine downtime and I now know that you deliver on your promises. In the past other spindle repair vendors talked a big game and consistently failed to deliver. You not only delivered my spindle before the due date but you kept me informed throughout the entire repair process.

Northland Customer

You performed a miracle with my BIG PLUS spindle. After crashing the spindle severely damaging the taper we found that a replacement spindle was not only cost prohibitive but had a long delivery. Your repair was a fraction of the cost of new and you never would know that the spindle was damaged to the extent it was.

Northland Customer