Abstract: An improved chuck for supporting elongated work pieces having conical end portions, such as single crystal ingots used to fabricate semiconductor wafers, while such. The chuck is typically used in a lathe for positioning and allowing rotation of the work piece during a grinding procedure that results in optimal work piece diameter. The chuck comprises a ring-shaped base, or socket, having a cavity defining a central axis therethrough and a series of fastener holes for securing the base to a headstock or tailstock of a lathe. The base receives within the cavity a portion of a chuck insert. The chuck insert defines a work piece support surface that is coaxial with the central axis when the chuck insert is disposed in a nominal position within the cavity of the base. The work piece support surface will typically define a continuous, arcuate, convex surface capable of supporting work pieces having conical end portions of varying diameters.