Reduced-friction thread forming or thread cutting screw

  • US 5,795,120 A
  • Filed: 05/13/1996
  • Issued: 08/18/1998
  • Est. Priority Date: 05/13/1996
  • Status: Expired due to Term
First Claim
Patent Images

1. A screw for creating threads in a workpiece, the screw comprising:

  • a cylindrical shank;

    a work holding portion on the cylindrical shank having a plurality of helical threads of a substantially constant crest diameter, a substantially constant root diameter, a substantially constant pitch diameter, and circular cross-section located thereon;

    a lead portion located at a first end of the cylindrical shank having at least a portion of a helical thread located thereon;

    a forming portion intermediate the work holding portion and the lead portion and having at least one full thread located thereon having a crest diameter which is greater than the crest diameter of the plurality of helical threads on the holding portion, a root diameter which is larger than the root diameter of the plurality of helical threads on the holding portion, and a pitch diameter which is proportionally greater than the pitch diameter of the threads on the holding portion; and

    a coupling means located at a second end of the cylindrical shank opposite the first end and capable of coupling with a driving tool.

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