This month I would like to discuss Anti-Friction bearings. Specifically the tapered bearings used on the hob and work spindles on the later Barber-Colman hobbing machines. Barber-Colman used Timken tapered roller bearings on these spindles. I have found that many customers have replaced these bearings over the years and did not have the proper information available to set the torque as required. Too much torque and of course the bearings wear much too rapidly, and too little torque and there is excessive looseness in the spindle under cutting pressures. The tables below show the proper torque requirements for the most common machines.

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