Partial blade connection at the centre of a fixed cutter bit

摘要

A fixed cutter drill bit 500 includes a bit body having a plurality of primary blades 501 extending radially from a bit centre area, wherein the bit centre area has a partial connection 505 between at least two of the plurality of primary blades 501. The partial connection can be a continuous curve, concave (fig 8) or flat (fig 9). The fixed cutter drill bit 500 further includes at least one cutter 502 disposed on at least one of the blades 501. Also claimed is a method of designing a fixed cutter drill bit of the type described above and a method of manufacturing said bit.