Parker-Majestic 1418-6, 3600 RPM stator drive, grease lubrication, hub OD taper
The devil is in the details.
Our customer found this grinding spindle in their stores with an eight year old toe tag on it. The tag indicated that the spindle needed service because the front shaft nut had come loose during operation which caused the bearings to lose preload. We confirmed this when the front bearings felt very rough when rotated by hand. It was also evident that the spindle had been recently rebuilt prior to this event, as evidenced by the clean, white grease in the bearings and the absence of any coolant contamination. Our inspection and dimensional evaluation also uncovered a significant deviation in the front bearing housing ID which was oversized and egged +5/+10µ where the ISO tolerance is ±6.5µ.
After grinding, chrome plating and finish grinding the front housing ID, we reassembled the spindle with all new bearings. We applied thread locker to the front shaft threads to avoid a repeat of the mistake apparently made by a previous rebuilder. While we did uncover a dimensional deviation which would have eventually proved detrimental to bearing longevity, the spindle should have run for quite some time if the nut had been properly secured.