The invention relates to methods of stabilizing bone implants, comprising inserting a self tapping implant having at least two helical grooves running in opposite directions around the implant.

Fasteners, drivers, and fastener systems constructed wherein example fasteners have driver engageable surfaces on or within a shank tip of the fastener. Example embodiments are included where at least one of the installation and removal surfaces are configured to define a segment of a spiral. Some example embodiments are also included where the installation and removal drive surfaces intersect an enlarged core diameter in an inner transitional surface that extends between the installation and removal surfaces of adjacent wings. Embodiments include fasteners with installation and removal drive surfaces on or within a shank tip of fasteners.

Fasteners, drivers, and fastener systems constructed wherein example fasteners have driver engageable surfaces on or within a shank tip of the fastener. Example embodiments are included where at least one of the installation and removal surfaces are configured to define a segment of a spiral. Some example embodiments are also included where the installation and removal drive surfaces intersect an enlarged core diameter in an inner transitional surface that extends between the installation and removal surfaces of adjacent wings. Embodiments include fasteners with installation and removal drive surfaces on or within a shank tip of fasteners.

The present invention prevents the occurrence of variation in the lead of a threaded section of a machined article (19a) resulting from the effects of thermal expansion of the machined article (19a) during machining. A thermal expansion amount that relates to the axial direction of the machined article (19a) during machining is measured by measurement means (13), history information for the thermal expansion amount that relates to the machined article (19a) during machining is obtained from the result of the aforementioned measurement, and a control unit (17a) determines the relative rotational speed of a rotary drive shaft (11) or the feeding speed of an axial feeding device (16a) with respect to the next machined object (19a) that is to be machined on the basis of the history information for the thermal expansion amount of the machined object (19a) that has been machined.

The present invention prevents the occurrence of variation in the lead of a threaded section of a machined article (19a) resulting from the effects of thermal expansion of the machined article (19a) during machining. A thermal expansion amount that relates to the axial direction of the machined article (19a) during machining is measured by measurement means (13), history information for the thermal expansion amount that relates to the machined article (19a) during machining is obtained from the result of the aforementioned measurement, and a control unit (17a) determines the relative rotational speed of a rotary drive shaft (11) or the feeding speed of an axial feeding device (16a) with respect to the next machined object (19a) that is to be machined on the basis of the history information for the thermal expansion amount of the machined object (19a) that has been machined.

A locking nut system includes a threaded member with a first threaded area having a first thread direction and a second threaded area having a second thread direction opposite the first thread direction in which a plurality of crests extend across the first and second threaded areas with a constant pitch between the crests such that minimal material is removed, structural integrity is maintained, and a first nut secures the threaded member to a workpiece and a second opposing nut renders the first nut stationary.

A machine tool and a control device for the machine tool for shortening the machining time of a workpiece in a case where the relative and reciprocal vibration of workpiece holder and tool post in the radial direction of the workpiece is stopped during a period from an initial point until when the workpiece and the cutting tool come into contact with each other is provided. In the machine tool, when threading the workpiece to form a threaded portion on the workpiece by relatively moving the workpiece and the cutting tool in the feed direction while relatively rotating the workpiece and the cutting tool 130 to perform multiple times of cutting processes along the same cutting path in a predetermined spiral form, the cutting tool is brought closer toward the workpiece in the feed direction from a predetermined initial point at which the workpiece and the cutting tool are separated from each other, the workpiece and the cutting tool come into contact with each other, and the threading is started with the contact. During the period from the initial point until when the workpiece and the cutting tool come into contact with each other, a controller stops the vibration of the cutting tool, and, in continuous cutting processes in the multiple times of cutting processes in the threading, the control means sets a phase position of the tool post in the vibration direction and stops the reciprocal vibration so that, when the workpiece and the cutting tool come into contact with each other, each of the continuous cutting processes has a predetermined phase in the reciprocal vibration relative to a rotation phase of the workpiece at the start of the threading.

A machine tool and a control device for the machine tool for shortening the machining time of a workpiece in a case where the relative and reciprocal vibration of workpiece holder and tool post in the radial direction of the workpiece is stopped during a period from an initial point until when the workpiece and the cutting tool come into contact with each other is provided. In the machine tool, when threading the workpiece to form a threaded portion on the workpiece by relatively moving the workpiece and the cutting tool in the feed direction while relatively rotating the workpiece and the cutting tool 130 to perform multiple times of cutting processes along the same cutting path in a predetermined spiral form, the cutting tool is brought closer toward the workpiece in the feed direction from a predetermined initial point at which the workpiece and the cutting tool are separated from each other, the workpiece and the cutting tool come into contact with each other, and the threading is started with the contact. During the period from the initial point until when the workpiece and the cutting tool come into contact with each other, a controller stops the vibration of the cutting tool, and, in continuous cutting processes in the multiple times of cutting processes in the threading, the control means sets a phase position of the tool post in the vibration direction and stops the reciprocal vibration so that, when the workpiece and the cutting tool come into contact with each other, each of the continuous cutting processes has a predetermined phase in the reciprocal vibration relative to a rotation phase of the workpiece at the start of the threading.

A method for cutting a thread on a rotating workpiece by means of a cutting tool having a cutting edge. The method includes sequentially performing a number of passes, each pass includes simultaneously moving the cutting tool and/or the workpiece relative to each other along and oscillating the cutting tool towards and away from workpiece rotational such that the cutting edge exits and enters the workpiece forming an air cut. The air cuts performed in a final pass are longer than all the other passes.

A bone plate system for internal fixation of bone fractures includes a bone plate having a plurality of bone plate holes. The holes are constructed to receive either a non-locking, locking, or variable-angle locking bone screw. The holes have discrete columns of teeth or thread segments arranged around the inner surface of the hole for engaging threads on the heads of locking and variable-angle locking bone screws. Conventional locking bone screws engage the bone plate coaxially with the central axis of the bone plate hole. Variable-angle locking bone screws can engage the bone plate at a selectable angle within a range of selectable angles relative to the central axis of the bone plate hole. The head of the variable-angle locking screw is at least partially spherical, and the thread thereon has a profile that follows the arc-shaped radius of curvature of the spherical portion of the screwhead.