PURPOSE: To make a circular blade securable uniformly and tightly to an arbor, by making a coefficient of thermal expansion different between the circular blade and the arbor in time of clamping the former to the peripheral surface of the latter, while heating both in a way of circulating a heat medium around an inside cavity of the arbor.

CONSTITUTION: When a circular blade having a ringlike edge is secured tight to the peripheral surface of an arbor 2 provided with a circulation feed system for a heat medium, first a spacer 14 and the circular blade 13 are alternately inserted into the arbor 2 and tacked with a fixed nut 15 for the time being. Next, after a duplex rotary joint 4 is attached to an opening end of the arbor 2, the heated medium is circulated around an inside cavity 3 of the arbor 2 by means of a pump 8 via pipes 5 and 7. With this method, both the arbor 2 and the circular blade 13 are heat-expanded for their diametral expansion whereby a diametral difference between them is reduced in proportion to a rise in temperature, while the arbor 2 is uniformly expanded as specified.