Importance

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Abstract

The present invention relates to improvements in devices for use as grinding cups for grinding the hard metal pins or working tips of drill bits and more specifically, but not exclusively, for grinding the tungsten carbide cutting teeth or buttons of a drilling head and the means for detachably connecting the grinding cups to the grinding machine. The grinding cups have top and bottom surfaces and consist of a lower grinding section and an upper body section. The grinding section is formed from a material capable of grinding the tungsten carbide button bits such as a metal and diamond matrix. The peripheral edge in the bottom surface may be bevelled to facilitate the removal of steel from the face of the bit around the base of the button during grinding. A centrally disposed convex recess is formed in the bottom surface of the lower grinding section having the desired profile for the button to be ground. The upper body section has a centrally disposed cavity formed in the top surface of the grinding cup. This cavity is shaped and sized to permit the grinding cup to be detachably connected to the drive member of a grinding machine and rotated during the grinding operation. One or more passageways connect the floor of the cavity in the top surface of the grinding cup with the convex recess in the grinding section to permit a coolant, preferably water, optionally mixed with cutting oil, to be provided to the surface of the button during grinding, through one or more outlets.

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First Claim