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TOS W100A Boring Mill Spindle Draw Bar Motor Assembly Issues


Mar 14, 2006
NW Pennsylvania
Our 45 Year Old TOS 100A HBM is having issues with the spindle draw bar tightening/loosening assembly.
The motor and gear assembly on the rear end of the spindle that tightens and loosens the drawbar is in need of some TLC. I have a manual but there is nothing concerning this area.
As far as I know, the motor starts turning when the operator pushes the "RELEASE TOOL" button.
It continues turning until a limit switch is tripped by the drawbar linear movement. The motor then continues to spin until it coasts to a stop. The same thing happens when the operator presses the "CLAMP TOOL" button. The motor is connected to the drawbar through a planetary gear set with a very high ratio. As far as I can tell, the motor turns the gearbox which turns a threaded stud. The stud pulls/pushes a keyed block that pulls/pushes the drawbar. There are 6 or 8 heavy bellville washers that I believe are used to manage the amount of force when clamping different tools into the spindle taper. There are thrust bearings that allow the drawbar to rotate with the spindle. Does anyone have any experience with this unit? Please let me know if you think you could point me to the finish line.
Thank you!


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