A cutter that can be mounted to a workpiece for cutting a cope at a prescribed arc at a selected radius and angle. A support frame mounts a band saw for pivotal movement about a first axis, parallel to the saws cutting flight. The support frame is mounted to a central workpiece clamp for pivotal movement about a second axis that is parallel to the first. The clamp secures the workpiece to the support frame, centered on a plane parallel to the first axis. The saw blade can thus be swung through an arc representing the outside diameter of a second workpiece that is to intersect at a prescribed angle with the clamped workpiece.