Shank taper accuracy AT3 or better. Made of alloy forged steel for long, durable service life. Hardened to RC 52-56 and ground to ensure maximum accuracy. Face is held perpendicular to centerline within 0.0002". Pilot diameter is sized for precision fit with cutter and is keyed for positive drive. Heavy duty locking RH nut and 5 arbor spacers are included - 1/16", 1/8", 1/4", 3/8", 3/4". For more spacers see page 549. Retention Knobs are sold separately.
