Claims
- 1. A method of manufacturing a rotary drill bit including the steps of:
- forming a main body part from metal;
- applying to at least a part of the outer surface of the main body part a coating layer of a material which liquefies at elevated temperature;
- applying to at least the coated body part mould-forming material to provide a self-supporting mould surrounding the coated body part;
- raising the temperature of the body and surrounding mould sufficiently to liquefy the coating material and drain it from the mould;
- packing the cavities left by the coating material with powdered matrix material; and
- infiltrating said matrix material with a binder alloy at elevated temperature to form a solid infiltrated matrix layer on the bit body part corresponding in configuration to the layer of coating material previously applied.
- 2. A method according to claim 1, including the step of forming apertures in said main body part and locating formers in said apertures prior to applying said coating layer to the main body part, said formers projecting from the main body part by a distance which is greater than the thickness of said coating layer so that the formers project through said coating layer, said formers being removed and replaced by operative elements of the drill bit after the formation of said solid infiltrated matrix layer on the main body part.
- 3. A method according to claim 2, wherein at least some of said apertures comprise holes pre-drilled in the main body part and said operative bit elements comprise cutters at least partly inserted into said holes after formation of the solid infiltrated matrix layer and removal of said formers.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9500659 |
Jan 1995 |
GBX |
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Parent Case Info
This is a Continuation Application of U.S. patent application Ser. No. 08/584,852, filed Jan. 11, 1996, now U.S. Pat. No. 5,732,783.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4667756 |
King et al. |
May 1987 |
|
5732783 |
Truax et al. |
Mar 1998 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
9001384 |
Feb 1990 |
WOX |
Continuations (1)
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Number |
Date |
Country |
Parent |
584852 |
Jan 1996 |
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