A method for machining grooves in the surface of a workpiece in which a dummy groove is machined in the surface of the workpiece by moving a cutting tool relative to the workpiece in a first machining direction of the workpiece, then orienting the cutting tool 180 degrees as compared to the first machining, and subsequently second machining the dummy groove by moving the cutting tool in a second direction opposite to the first direction. A displacement of a cutting edge of the cutting tool, caused by the first and second machining of the dummy groove is measured. A groove is machined with the cutting tool in a forward stroke and then a return stoke with the cutting tool rotated 180 degrees between the strokes. A relative position between the workpiece and the cutting tool during the forward and return strokes is corrected so as to eliminate the displacement.

An installation tool for fastening a top plate to a roof support member and other structural connections is adapted to drive threaded fasteners at a pre-established angle. The tool preferably includes a rotary driver assembly and a telescopic tube assembly. A guide head assembly is mounted adjacent the outer end of the telescopic tube assembly. Locating or reference structures function to properly precisely set the drive angle of the fastener. Various indicators mounted to the guide head indicate the flush position of a locating surface or reference structure. The flush indicators may employ a projection, a flag, an LED or an audio module.

Surgical impact driver adaptors may be connected between a powered surgical instrument and a driven surgical device when performing surgical procedures, such as those involving the implantation of a surgical implant into bone, for example. During surgical procedures, the surgical impact driver adaptors may limit a transfer of a rotational force from the powered surgical instrument to the surgical device until a sufficient axial force is applied to the impact driver adaptor from the powered surgical instrument.

An ultrasonic micron precision molding apparatus includes: an ultrasonic generating module, a tool and an amplitude transformer. The ultrasonic generating module provides ultrasonic frequency vibration. The tool is disposed below the ultrasonic generating module, and has a micron-level precision structure. The amplitude transformer is disposed between the ultrasonic generating module and the tool and has a first section and a second section, the first section is disposed at the junction of the amplitude transformer and the tool, and the distance between the second section and the tool is longer than the distance between the first section and the tool, wherein the width of the first section is greater than the width of the second section.