Abstract: A screwdriver blade has faces formed on front and back sides of a shank. Each face has a drive surface extending from each side edge inward toward a longitudinal axis. Each drive surface is inclined relative to a plane containing the axis and bisecting each of the side edges. A thickness of the blade increases from the shank distal end. Each of the drive surfaces appears curved when viewed in a distal end view. Each of the drive surfaces extends from the shank distal end to a face proximal end. A central portion between each of the drive surfaces may also appear curved when viewed in a distal end view, or it may be flat. The drive surfaces and the central portion may be formed at a single radius of curvature. The central portion may have a increasing width from the distal end or it may have a constant width.

Abstract: A manufacturing process for a chain tool attached to a bicycle folding tool included the following steps: Material preparing step: a rod with a length is prepared. Manufacturing step: the rod is milled via a milling cutting step to form a chain fixing groove, a detaching portion, an axial groove and a screwing portion, the chain fixing groove having a retaining wall, the retaining wall being milled to form an arc notch, the screwing portion being threaded to form a threaded hole via a drilling and tapping step. Heat treatment step: after the manufacturing process, the rod is heat treated. Sheet metal part assembling step: a sheet metal part is assembled to the chain tool by at least one connecting part; therefore, the chain tool is attachable to the sheet metal part.

Abstract: A screwdriver blade has faces formed on front and back sides of a shank. Each face has a drive surface extending from each side edge inward toward a longitudinal axis. Each drive surface is inclined relative to a plane containing the axis and bisecting each of the side edges. A thickness of the blade increases from the shank distal end. Each of the drive surfaces appears curved when viewed in a distal end view. Each of the drive surfaces extends from the shank distal end to a face proximal end. A central portion between each of the drive surfaces may also appear curved when viewed in a distal end view, or it may be flat. The drive surfaces and the central portion may be formed at a single radius of curvature. The central portion may have a increasing width from the distal end or it may have a constant width.

Abstract: A coated carbide tap comprises a substrate consisting of tungsten carbide cemented with 12 to 16% by weight cobalt with additions of small amounts of transition metal carbides added to restrain grain growth, and may also contain low levels of impurities that might be picked up during processing. The substrate is coated with a layer of metal nitrides, carbides, carbonitrides, borides and/or oxides, the metal being chosen from one or more of the following: aluminum, silicon and the transition metals from Groups IVa, Va, and VIa of the Periodic Chart. The coating may comprise a monolayer and/or alternating layers optionally with varying chemical composition.

Abstract: The invention concerns a process for the manufacture of a cutting insert (1) for thread cutting, with several cutting teeth (2-6) simultaneously engaged in incrementally cutting the thread profile. The blank is manufactured by pressing and sintering so that the relief angles of the flanks of the side cutting edges (9,10) of the individual teeth (2-6) are at least 3.degree. and the profile depth of the final cutting tooth (6) which makes the finishing cut on the thread fits within the required final measurement tolerances, while the thickness of the cutting insert (1) and the tooth width (b) of the cutting teeth (2, 3, 4, 5, 6) are oversized. Subsequently, the blank is mechanically processed on the back face (7) and/or the front face (8) until the tooth width (b) of the cutting teeth (2, 3, 4, 5, 6) and the thickness (d) of the cutting insert (1) fit within the required final measurement tolerances.

Abstract: A method of forming a threading tool for producing a thread of varying pitch in a work piece by relative rotary and axial movement between the tool and work piece. The tool is constructed to have a series of threading projections including a first series of pre-forming projections for initially producing a partial thread and groove in the work piece, and one or two final projections for reshaping the partial thread to have the varying pitch.