Our customer indicated that this OD grinding spindle had locked up during operation. Upon inspection, we found that a lump of grinding swarf had penetrated the spindle interior through an incoming oil port. This particulate contaminant became lodged in the area between the ID of the rear bronze bearing and the OD of the spindle shaft. The rotation of the shaft smeared the particulate onto the ID of the bronze bearing, scarring it while also causing the shaft to rub out on the front bronze bearing and the thrust bearing.
Because the radial bronze bearings in this spindle are designed as tapered lobes, we could not rework the bearings on one of our Kellenberger cylindrical grinders. Our course of action was to rescrape the three bearings by hand so that the spindle oil would create the proper hydrodynamic film. The tolerance for radial motion at the front & rear bronze bearings had to be between 4 and 6 microns, while the thrust bearing had to limit axial motion to less than 4 microns. Fortunately, the spindle shaft was not damaged and required no attention. Because we did not receive the entire wheelhead assembly, we could not test run the spindle. On follow up, our customer reported that the spindle was functioning better than when it was first installed.
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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.
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.
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
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.
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!
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.
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.
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.
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.
Catastrophic bearing failure was the main cause of this spindle malfunction
Continue reading to learn how Northland Tool performed this repair and converted a Weiss GHK 176239 spindle from grease-injected to permanent grease lubrication…