Abstract: A drilling device for drilling holes in structural steel shapes utilizes a control system having a pair of control pistons to set the drill bit at an optimum distance from the workpiece for repeated drilling of holes through material of a given thickness. The control device responds to position switches sensing the positions of the drill-feed cylinder and the control pistons.

Abstract: An antiscattering device for the collection of waste material (dust, shavings) produced in the course of drilling, milling and similar operations, to be fitted in the most appropriate way on machine tools and basically made up of a bellows shaped bell (e.g. frustum-conical), provided, if required, with an axially elastic vacuum cleaner or extractor--which can be fitted on the machine tools themselves. This bell is permanently or temporarily secured to the frames of machine tools (e.g. manually, on a drill), coaxially to the drill bit while its base, provided with a seal ring, rests on the surface of the material to be drilled, thereby creating, with its shell, a receptacle where the waste material collects.

Abstract: A retention knob for reversibly locking a tool holder to a locking device in which the shaft of the retention knob has a pair of opposed recesses separated by non-recessed portions to thereby provide a significantly stronger locking engagement between the tool holder and the locking device. Also disclosed are cutting tool assemblies employing the retention knob.

Abstract: The invention is a split-point twist drill for use in drilling holes in sandwich structures composed of a combination of organic matrix composite, titanium and steel. The drill (20) preferably has a web thickness (50) prior to splitting of between 23 and 27 percent of the drill diameter, a point angle (60) between 132 and 138 degrees, a web taper from the point to flute run out between 0.015 to 0.020 inch per inch, a chisel-edge angle (44) between 115 and 121 degrees and a splitting angle (70) between 127 and 137 degrees. Further important dimensions are a helix angle (24) of between 28 and 32 degrees and a lip relief angle (62) of between 10 and 14 degrees. Additional important splitting dimensions are a positive notch rake angle (74) of between 5 and 10 degrees, and an angle of the notch (72) to the drill axis between 32 and 38 degrees.

Abstract: The present invention discloses a torque restraining device to resist the lateral shifting or rotation of a self adhering drill unit due to the torque generated by the drill motor. The torque restraining device includes a penetrating member mounted on the bottom of the drill unit for penetrating the work surface to prevent rotation of the drill unit during use. The penetrating member is embedded by the action of the drill unit being pulled to the work surface when the mounting base of the drill unit is activated. In the preferred embodiments, a protective sleeve is reciprocally mounted about the penetrating member to encase the penetrating member to prevent damage when the base is not activated. Upon activating the base, the sleeve retracts to expose the penetrating member for penetration into the work surface.