A lathe has a plurality of turret positions with at least one having a toolholder, a pair of blades projecting from one end of the toolholder with the toolholder structured to assume a first position with a first blade machining said workpiece which is rotating in a first direction and a second position with a second blade structured to assume a second position with the workpiece rotating in the other direction. The toolholder remains fixed during machining. Related methods and toolholders are disclosed.

A clamping tool holder includes a tool holder body and a clamp for clamping a cutting insert. The clamp causes the cutting insert to press against the bottom and the side walls of an insert-receiving pocket of the tool holder body. The tool holder body has an inclined surface sloping inward in a direction away from the insert-receiving pocket. The clamp has an inclined surface that acts as a ramp with the inclined surface of the tool holder body. When a clamp screw is tightened, a nub of the clamp engages an inside rearward surface of a mounting bore of the insert with face contact and a contact pad engages a top surface of the cutting insert. As a result, the clamp exerts a force downward and rearward force on the insert. In one aspect, the nub has a polygonal cross-sectional shape.

A toolholder and method for use with a cutting insert having a clamping opening, comprising a toolholder body and a clamp pivotably mounted to and contacting the toolholder body and pivotable between a first position in which a protrusion of the clamp is disposed in a position in which it is arranged to be received in the clamping opening in the cutting insert to secure the cutting insert to the toolholder body and a second position in which the protrusion is spaced, relative to the toolholder, upwardly from the first position so that the cutting insert is not secured to the toolholder body by the protrusion. A resilient member is arranged relative to the clamp to urge the clamp to the first position and to resist pivoting of the clamp to the second position. An opening in the clamp may receive a portion of a separate lever.