Abstract: A spot drilling and centering drill including a body having a cylindrical head portion and a replaceable indexable insert mounted in the head portion. A V-angled slot is formed directly in the head portion. The insert has two V-angled cutting surfaces with a drill point, each cutting surface fitting within the V-angled slot to locate the drill points on the centerline of rotation of the drill.

Abstract: A boring tool assembly performs both the rough and finish cutting operations upon a metal work piece without power activation or manual adjustments of the tool units between the cutting strokes. The assembly includes a boring bar having a pair of fixed, diametrically opposed rough cut tool units, and a pair of retractable finish tool units diametrically opposed to each other also. The tool units are automatically operative in response to either the rough cut or the finish cut of the boring tool assembly. Spring biased plungers normally pivot the finish cutting units toward their cutting positions. During the initial or rough cutting operation, forces act upon the heel of the finish tools causing retraction from the cutting position. This is possible due to the cutting edge configuration and angle of orientation of the tools, the positioning of the tools on the trailing side of the boring bar centerline, and the direction of advancement of the boring bar.

Abstract: A device for undercutting a rotating workpiece is provided wherein the tool carried by the toolholder is actuated into and out of engagement with the workpiece at predetermined feed locations. A base forms the mounting for the undercutter attachment with the toolholder being pivotally mounted on said base. The tool is moved axially in one direction along the workpiece to provide cutting. When the end of the travel has been reached, the tool moves in the opposite or return direction and the tool is automatically disengaged prior to reaching the start of the undercut portion. The actuator for the tool includes a pivoted arm and stationary trip cam on the machine tool. A positive latch holds the tool in the cutting position and a release trigger engages the trip cam to release the latch during the return feed at the proper position. The latch comprises a biased pin and the pivotal toolholder is biased by a spring activated cylinder.