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: A tap having a main body having a crest, a heel, and an outer circumference is disclosed. The tap main body has a male screw part at the crest side. At this male screw part, a plurality of grooves opening to the crest and the outer circumference of tap main body is formed. A tap main body has a cutting edge at each ridge part defined by a wall of said plurality of grooves and an outer circumference of a male screw part. These cutting edges each have a crest part and a heel part. The crest part of at least one cutting edge has an axial rake angle which differs from an axial rake angle of the crest part of another cutting edge.

Abstract: A tapping attachment for driving a tapping spindle constructed to be adapted for both direct drive and reverse drive of the spindle. The drive of the spindle is by way of a resiliently mounted dog ring having rigid radially extending drive dogs, extending radially outwardly and inwardly from a drive ring. The driving dogs are rigid, having slanting sides to accommodate clutching engagement and disengagement. Clutching engagement and disengagement occur as a result of relative axial movement as between the attachment and the drive spindle. The drive spindle has a central bore in which is provided an insert member having an axial bore which is connected to a flexible tube within the bore of the spindle, which accommodates relative axial movement, the flexible tube communicating with a similar bore in a tap itself. These bores provide a channel for continuously supplying coolant to the machine and to the spindle itself.

Abstract: Machine thread cleaning tool which is quick and simple and does not recut threads and therefore does not require replacing connecting components, but merely removes corrosion and dirt. The tool, or chaser, does not require that components extending outward from the machine casing be removed and the chasing can be accomplished using a basic spanner wrench. The tool comprises a disk with bores through the center thickness and parallel grooves running along the circumference of the disk and across the entire thickness.

Abstract: An electronic thread tapper includes a cam-operated feed mechanism which drives the tap carriage rigidly in the advance direction only. Separate force means are employed to move the carriage in the retract direction when the tap is being withdrawn from the work material. Spindle and feed motors operate separately, but are cycle-coordinated during a dwell period between tapping strokes. By measuring any position error developed between the spindle and feed positions, a fault condition, such as a worn tap, a workpiece material defect, or an obstruction in the machine can be sensitively detected.

Abstract: A rotary metal cutting tool for forming threads on the insides of a bore, drilling a bore or otherwise shaping a bore, which tool is fabricated from a metal injection molded blank of appropriate tool steel to provide improved tool wear. The tool, which may be a tap, includes a transverse stress relief ring for reliably localizing the point of tool failure under overstress conditions. A polygonal, e.g., hex, surface on the shank provides means for engaging the shank with an extraction tool to remove the broken remains of the tool from the bore after the tool fails. A conventional O-ring seal is installed in the stress relief ring to provide protection from flying metal particles upon failure.

Abstract: There is a tap whose thread portion 2 forms a cutting section 5 and a guiding section 6 and is provided on a plurality of adjacent thread teeth of the cutting section 5 with a relief 8. It is desirable that a further machining measure be provided for the tap whereby favorable compromises can be obtained with respect to guidance and friction. This is achieved in that the relief 8 of the adjacent cutting-section 5 thread teeth--seen in a longitudinal direction--have a clearance angle which varies increasingly or decreasingly. Varying the relief enables the requirements with respect to avoiding incorrect tapping and avoiding friction-generated cold welding to be met and matched up in an improved manner.