Machine tool operation Volume 2

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ..."Grinding Wheels"). Keep the wheel clean and true and take light fast cuts to avoid drawing the temper of the cutter. HOLDING THE CUTTER The revolving main spindle of the milling machine carries with it the milling cutter. The cutter may be held in several different ways. Perhaps the method most commonly used for holding the milling cutter is by means of an arbor. 163. Milling machine arbors (Fig. 190) are made in various lengths and in standard diameters of 1, 1 and 1 in. Fig. 190.--Milling machine arbor in position. Milling machine arbor. S, machine spindle; T, taper shank of arbor; C, collars. The outer end of the arbor is threaded to receive the nut. In machines, Brown & Sharpe for example, where cutter normally runs left hand the arbor and nut are threaded left hand. Thus the pressure of the cut does not tend to loosen the nut. B, bushing for journal bearing in bearing support or yoke Y. Dotted lines show yoke center in end of arbor. The shank is made taper to fit the taper hole in the spindle, and the other end is threaded to receive a nut. The remaining portion of the arbor is made cylindrical. Collars are fitted freely over this part of the arbor and by means of the nut one or more cutters may be clamped between the collars. The collars being of different lengths and removable, permit of cutters of various lengths (or thicknesses) being clamped and also permit of locating the cutters in the desired position on the arbor. The arbor is supported by the yoke from the over arm either by a center or in a bearing in the yoke. The bushing B which forms the journal in the outer bearing for supporting the arbor is of somewhat larger diameter than the collars and is ground to fit a bronze bearing in the arbor yoke. To avoid spring of the arbor, ...