Abstract: A cam operated machining unit for use in providing principally, either, a drilling, reaming, counterboring, trepanning or threading function, upon another component being machined, the unit includes a spindle rotatably supported within a quill, with the spindle having the tool held therein, with the combination of the spindle and quill being disposed for longitudinal shifting, especially in a rapid approach, a constant feed speed, and then a rapid retraction from its position of performing a machining function upon the component being worked; the composite spindle includes a first gear, and which interconnects by a series of intermediate gears with a cam shaft arranged gear, with the cam shaft holding a cylindrical cam which is intermated with conjugate cam followers, that are fixed upon the quill, all being operatively associated with drive means furnishing the rotational movement for turning of the spindle and its tool, with the intermediate gears translating its rotational force to the cam for inducing the