US Patent 7255518 Insert seat formed of ridges

A tool body includes an insert seat for receiving a cutting insert for chip-removing machining. The insert seat includes a bottom surface and support surfaces upstanding from the bottom surface. Each support surface comprises at least three ridges separated by grooves. Each groove has a depth greater than zero and no greater than 0.015 mm. An insert mounted in the seat by a screw has a center hole whose axis is offset from the axis of a threaded hole of the body in which the screw is connected. That offset distance creates a prestress of the insert toward the ridges. The depth of the grooves (i.e., the height of the ridges) is substantially less than the distance of the offset.