Black Decker Inc.

Thomas J Quinn

Florian Probst

David N Johnson

David B Lee

Glen V Steinbrunner

Albert Leidl

William R Stumpf

Rickey James Thomas

Abhijeet P Joshi

Alfons K Wetzl

Maurice L LaPointe

Rudolf Jungwirth

Maurice Lapointe

A chisel includes an elongate shank portion composed of a first steel, and a working end portion composed of a second steel that is different than the first steel. The working end portion is joined to the shank and configured to chisel a workpiece. The joined shank portion and working end portion has been heat treated to cause the first steel of the shank portion to adopt a first microstructure comprising bainite, the second steel of the working end portion to adopt a second microstructure comprising martensite, and the working end portion to have a greater hardness than the shank portion.

Chisels

A point chisel includes a substantially cylindrical shank and a working end region that tapers to a point. The working end region has at least three converging substantially planar surfaces, each with a protruding elongate rib extending along at least part of its length. Adjacent surfaces meet along at least part of their length at substantially straight edges between adjacent ribs. A flat chisel includes a substantially cylindrical shank and a working end region with a pair of converging substantially planar surfaces that include a plurality of protruding elongate ribs extending along at least part of its length. Each rib has, along the majority of its length, a substantially constant height above the surface from which it protrudes. Each chisel is made from steel, with the shank having a bainitic microstructure and the working end region having a martensitic microstructure.

A combination drill bit for use in both hand held drills and stationary drill presses has a shanking end, a working end and a helical flute portion between the shanking and working ends. The helical portion has a helix length (L) of The drill bit has a core that is tapered from the working end to the shanking end. A web thickness length at the working end is 10% to 35% of the diameter and the thickness length at the junction of the shanking end is 70% to 90% of the diameter. The drill bit is manufactured from a high speed steel including at least 5% by weight of cobalt.

Metal cutting drill bit

Chisel

Chisel having a contrast of color

A cutting head for a drill bit has a body with an overall cruciform shape. One pair of opposing arms defines a main cutting edge. The other pair of opposing arms defines an auxiliary edge. The main cutting edge is defined by rake surfaces and relief surfaces. Each rake surface and relief surface is defined by a plurality of facets. The main cutting edge includes a chisel edge. A first pair of planar rake facets, one on each end of said chisel edge, and a first pair of planar relief facets, adjacent said chisel edge, defines a portion of the cutting edge. A remaining portion of the main cutting edge is defined at the apex of a plurality of curved rake facets and curved relief facets. The auxiliary edge is defined by a plurality of curved surfaces.

Drill bit including one piece cutting head

Growing community of inventors

Towson, MD, United States of America

Thomas J Quinn