Patents by Inventor Keith Siddall

Keith Siddall has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Twist drills
    Patent number: 4065224
    Abstract: A twist drill the cross-sectional shape of which is such that, although it can be sharpened on a conventional machine so that its cutting edges are contained in the surface of an imaginary cone, its cutting edges are curved and their lip rake is substantially constant radially outwards of the drill core.
    Type: Grant
    Filed: October 7, 1976
    Date of Patent: December 27, 1977
    Assignee: Osborn-Mushet Tools Limited
    Inventor: Keith Siddall
  • Twist drills
    Patent number: 3977807
    Abstract: A twist drill having primary lands and associated secondary lands the primary lands being relieved adjacent the major flanks so that each secondary land protrudes outwardly and forms a sizing flank for taking a "skimming" cut. The primary lands may be relieved either by being chamfered off at an angle or by the diameter across said primary lands being reduced for a limited distance from the major flanks.
    Type: Grant
    Filed: May 27, 1975
    Date of Patent: August 31, 1976
    Assignee: Osborn-Mushet Tools Limited
    Inventor: Keith Siddall