Abstract: A tool support adapted for use with a tool holder having an elongated shank which is mounted in a machine tool, is useful to support an insert for cutting deep grooves in a workpiece. The tool support has a body having a central body portion and a second body portion extending from the central body portion, which second body portion has a first surface portion adapted to support an insert thereon and a second portion extending arcuately from the first surface portion which is adapted to enter arcuate or circular spaces or grooves formed by the tool in a workpiece. The body portions are preferably integral and preferably includes a portion which engages the tool holder and inhibits vertical movement of the tool support relative to the tool holder and a third body portion adapted to cooperate with a clamping member to clamp the insert to the tool support.