Abstract: A male screw thread-formed member such as an insert having a thread cutting action has an exterior peripheral portion of substantially full V-thread form along which two or more angularly spaced apart flutes extend from one or both ends of the member, the member being provided with at least one non-helical rib initially of generally annular peripheral V-form at one or both ends thereof and on which is formed a varying reduced V-thread form which follows a helix corresponding to that of the full thread form whereby pointed cutting formations providing peaks of different radial heights and with some of them of offset disposition relative to the helix are formed on the or each rib at the flutes for effecting a distributed thread cutting action thereat, e.g., for use in thermo-setting plastic material.

Abstract: A rotary tool having a working part and a shank. The working part is formed by at least two axial portions of which the first portion is made with the profile of a twist drill for making a pilot hole, and the second portion is disposed axially between the first portion and the shank. The second portion is made in such a manner as to enlarge the pilot hole upon entering it and to ensure self-feed of the tool in the axial direction. This permits substantial reduction of required force for axial feed of the tool, improves productivity and allows making holes of different diameter with one and the same tool.

Abstract: A combination tap and die wrench is provided having a center portion with an aperture extending through the thickness thereof for receiving and retaining tapping apparatus and at least two oppositely extending arm portions extending outwardly from the center portion, each of said arm portions including a plurality of receptacles for receiving and retaining dies. An extension handle is also provided and may be secured to either of the arm portions at their outwardly extending ends. Storage means for tapping apparatus may be provided in the handle.

Abstract: The specification and drawings disclose a collapsible tap of the type including an elongated, cylindrical body or housing having an axially extending actuating plunger mounted for selective movement longitudinally of the body. The outer end of the plunger has a generally conical portion which functions to provide camming surfaces. Suitable chaser cutting elements are mounted for radial movement in the body. Each element includes a surface in engagement with a corresponding camming surface of the plunger such that axial movement of the plunger produces radial movement of the elements. The elements are maintained in engagement with the camming surfaces by clip members which extend radially from the conical portion of the plunger with resilient, laterally directed terminal portions that engage grooves formed in the sides of the elements.

Abstract: A tapping device having at least two components for use in rethreading damaged threads in a tapped opening or for tapping an opening in a workpiece, wherein the thread cutting member is inserted into the opening and its cutting surface is held in place and is pressed against the work surface by one or more guide members that have also been inserted into the opening and wedged tightly adjacent the cutting member. The cutting member and the guide member are then rotated as a unit and threads are tapped or retapped in the work surface.

Abstract: A rotary cutting tool having a cutting element at one end and a cylindrical shank at the other end terminating in a T-shaped mounting tongue member, and a tool support for holding the tool in floating engagement the support having a cylindrical body with a transverse T-slot in its end for receiving said tongue member, the slot having sliding clearances with respect to the tongue member, and the holder having a sleeve which is spring urged to cover the T-slot to retain the tongue member in it, the inner diameter of the bore through the sleeve having a small clearance where it overlies the shank of the tool so that the latter can move transversely to align the tool in a hole when it is in use.

Abstract: A threading tap, having the usual longitudinally extending flutes to provide lands therebetween. Each land is provided with screw-cutting teeth, and each land has at least one cross-groove formed therein of a length equal to at least two teeth and of a depth greater than the root depth of adjoining teeth. A cross-groove in one land is longitudinally off-set from a cross-groove in an adjoining land to provide for chip clearance and yet not materially weaken the structure of the tap.