The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 19, 1988
Filed:
Apr. 21, 1986
David Shirley, Cheltenham, GB;
NL Petroleum Products Limited, Gloucestershire, GB;
Abstract
A method of manufacturing by a powder metallurgy process a rotary drill bit including a bit body having an external surface on which cutting elements are mounted, and a passage for supplying drilling fluid to the surface of the bit. The method comprises forming a hollow mould for moulding at least a portion of the bit body, packing at least part of the mould with powdered matrix material, and infiltrating the material with a metal alloy in a furnace to form a matrix. Before the mould is packed with the powdered material, formers are positioned on the interior surface of the mould to project into the interior of the mould space and form sockets to receive nozzles, or studs on which the cutting elements are mounted. According to the invention, the formers are formed from material, such as austenitic stainless steel, having a coefficient of thermal expansion not less than that of the matrix material. The formers may have a surface coating of a ceramic, such as boron nitride, or other material which does not wet or react with the binder alloy or matrix material.