Chatter is often caused by lack of rigidity in the machine,workpiece, or the reamer itself. Correctionse may be made by reducing the speed,increasing the feed,putting a chamfer on the hole before reaming, using a reamer with a pilot (Figure H-127),or reducing the clearance angle on the cutting edge of the reamer. Carbide tipped reamers especially cannot tolerate even a momentary chatter at the start of a hole,as such a vibration is likely to chip the cutting edges.