Abstract: In a friction stir welding method, a tool is moved being rotated along portions to be joined of a work piece, where the portions include a corner with a smaller curvature that connect two portions with larger curvatures. The method includes the steps of setting the work piece on a supporting member, rotating the tool around a center axis thereof, moving the tool toward the work piece to penetrate a portion of the tool into the work piece at the portions to be joined, and moving and turning the tool along the portions to be joined. A rotation speed of the tool around the center axis thereof is decreased to be smaller at the corner with the smaller curvature than the rotation speed of the tool around the center axis thereof at the portions with the larger curvatures.

Abstract: Apparatus and methods for forming a thread of varying pitch by utilizing a threading assembly which includes a plurality of threading elements having thread cutting or forming portions on the different elements for engaging the work piece at different locations, with the assembly and work piece being driven both rotatively and at the same time axially relative to one another to form the thread. The rate of axial advancement per revolution between the work piece and each of the threading elements is varied, and the elements of the assembly are also shifted axially relative to one another during the rotary and axial movement, to give the thread its varying pitch.

Abstract: An apparatus for precision linear positioning of material along a frame, having carrier means for carrying the material juxtaposed above the frame, means for linearly moving the carrier means along the frame having a plurality of pneumatic cylinders each having an extendable and rectractable piston, the cylinders connected to each other in a series and including a first end pneumatic cylinder attached to the frame and a last end pneumatic cylinder attached to the carrier means, such that the carrier means is moved by the amount of the cumulative extension and retraction of the pistons, stopping means associated with each the pneumatic cylinder for limiting the extension of each the piston, and means for providing a controllable amount of air to each pneumatic cylinder to selectively control extension and retraction of each piston.

Abstract: What is proposed is a drilling attachment for use with a machine tool that rotates a workpiece in which the drilling apparatus is moved into an operative position to the workpiece by means of the machine tool slide and is rotated with the workpiece so that a drilling member associated with the rotating drilling apparatus is caused to rotate and to enter the workpiece while the same is rotating.