Single mold milling process

Abstract

A bit mold is milled using a turning stage which forms a base mold component and a base gagering component. Next, a blade milling stage is performed in which the base mold component and base gagering component are milled to define integral junkslot formers separated by blade regions. Lastly, a pocket milling stage is performed in which the blade regions and integral junkslot formers of the base mold component are milled to define a plurality of cutter pockets in primary and perhaps secondary rows. Each cutter pocket includes a seat portion and a face portion. The milling of the pocket milling stage provides, at one or more of the cutter pockets, a facet. This facet is provided in an area about the junkslot former associated with the face portion of the cutter pocket, the face portion having, due to the presence of the facet, a surface for matching a cutter core displacement end surface without voids of a size which would require the use of fill material. The facet is also provided on either side of the pocket associated with the seat portion to avoid the need to clay the sides of the displacement for providing top-loading clearances. The milling process at the pocket milling stage further supports definition of relief and erosion resistance features in the mold.