Free flow stabilizer

Claim 1

A bladed stabilizer for mounting in a drill string of a generally cylindrical configuration and a generally uniform outer diameter above a drill bit to ream and stabilize a bore hole, comprising: an upper body section having a generally cylindrical configuration, having an outer diameter which is diametrically spaced inwardly from the bore hole to form an upper annular flow area, and is substantially the same size as the outer diameter of the drill string; a lower body section formed with said upper body section and having generally cylindrical configuration, said lower body section having an outer diameter which is less than the outer diameter of said upper body section; said upper and lower body sections cooperating to provide a continuous internal body bore for the circulation of a drilling fluid such as air downwardly through said stabilizer; a plurality of spirally directed blades mounted on said lower body section in an equally circumferentially spaced relationship with respect to each other, the outer diameter of said mounted blades forming the reaming diameter of said stabilizer for reaming the bore hole to said reaming diameter; said blades and said lower body section cooperating to provide a net annular blade flow area with respect to said bore hole, which net annular blade flow area is greater than said upper annular flow area past said upper body section whereby the flow rate of drilling fluid and cuttings circulating past said blades is at least equal to the flow rate of such cuttings passing said upper body.