Brown & Sharpe 618 Spindle Rebuild
Possible cause of failure:
#1 front bearing contaminated with grinding dust (also evident behind front shaft nut and in the labyrinth.)
Wheel taper has 4-5µ runout.
Front housing ID is egged & tapered +5/+15µ (ISO is +/-6.5µ)
Rear housing ID was previously GPG'd over a pre-existing score line
Front shaft nut spanner holes have minor damage.
Clean, inspect overall dimensions.
Kiss grind wheel taper.
Grind, plate & regrind front and rear housing ID.
Rework front shaft nut spanner holes.
Replace bearings, gaskets & screws.
Adjust preload, balance, assemble and break in. Final quality control inspection.