This horizontal machining spindle was seized when it arrived at NTE. The OD of the shaft nose had rubbed out on the ID of the front cover, and the ID of the taper insert had poor tool contact with excessive runout. The tool retention force was very low incoming and we observed that the gripper fingers were damaged and had significant wear. We also noted that the rear actuator bolts and the sensor covers were loose, and that the spindle-side ceramic seal surface of the rotary union was chipped. We suspected that the front bearings had lost preload in a crash, which may have resulted in much of the previously-mentioned damage.
The 100mm front bearing journal of the spindle shaft was manufactured to be oversized +32/+35µ to accommodate the special preload of the front quad set of proprietary OEM angular contact bearings. Normal ISO tolerance for that journal when using non-proprietary bearings would be ±9µ. The decision was made to reduce the OD of the journal to make possible the use of non-proprietary high-precision bearings in this, and any subsequent rebuilds.
We performed a kiss grind of the OD of the shaft nose, the ID of the taper insert and the 100mm front bearing journal. After a thorough cleaning of all the other spindle components, we reassembled the spindle with all new bearings, Bellevilles, grippers, rotary union, seals, o-rings and assembly screws. Tool retention force was checked and found to be improved to within the correct range. During our five hour break-in test run of the rebuilt spindle we confirmed that the vibration & temperature readings were within specification. Hopefully our customer will not need to have this spindle rebuilt any time soon, but if they eventually do, the bearings needed will be more readily available at a lower cost.
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Possible cause of failure: Taper and od of shaft nose are damaged. Taper looks hand ground with a die grinder. Od of shaft nose has rub out with front cover ID. The drive dog and drive dog pock [...]
Toyoda FA400, 14000 RPM, oil mist lubrication, stator driven This spindle arrived at our facility after having been completely disassembled by another spindle rebuilder. In… [...]
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…