Bit manufacturing method

A method of manufacturing a drilling-related structure for drilling a subterranean formation, comprising:

• forming a first mold having a cavity configured to define a blank for said drilling-related structure by:
• providing a second mold having a cavity configured to define said drilling-related structure;
• lining said second mold cavity of said second mold with a lining material to a thickness substantially equal to a desired thickness of a layer of abrasion-resistant material around said blank;
• forming a male part within said lined second mold cavity;
• removing said formed male part from said lined second mold cavity;
• and
• forming said first mold around said male part to define said first mold cavity;
• inserting a core metal in particulate form into said first mold cavity;
• and
• sintering said core metal to form said blank.

A method of manufacturing a rotary-type drill bit element for drilling subterranean formations, comprising:

• providing a bit mold defining a cavity;
• substantially filling said bit mold cavity with powdered steel;
• exposing said bit mold to a heat source to at least partially sinter said powdered steel into a porous bit blank;
• removing said bit blank from said mold cavity;
• substantially sintering said bit blank to form a shrunken sintered bit core of at least one smaller external dimension than said mold cavity;
• placing said shrunken, sintered bit core abutted by a steel displacement back into said mold cavity;
• and
• loading said mold cavity with tungsten carbide powder in a space created between an inside surface of said mold cavity and said shrunken bit core.

A method of manufacturing a drilling-related structure used in drilling subterranean formations, comprising:

• forming a steel powder body;
• forming a mold around said steel powder body;
• removing said steel powder body from said mold;
• sintering and shrinking said steel powder body;
• placing said shrunken sintered body back into said mold;
• loading said mold with a carbide powder between said mod and said shrunken sintered body;
• providing a binder for said shrunken sintered body;
• and
• heating said mold until said binder liquifies and substantially infiltrates said shrunken sintered body and carbide powder.

A method of manufacturing a drilling-related structure for drilling a subterranean formation, comprising:

• forming a shell of abrasion-resistant material;
• inserting a preformed, sintered blank into said shell;
• and
• infiltrating said shell and said preformed, sintered blank with a binder.