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Centering Attachment

The Potter patent self-centering lathe attachment, shown in Fig. 56, will be found useful in rapidly bringing work to an accurate center, when pivoting, staffing, etc.

The attachment, which may be fitted to any make of American lathe, consists primarily of the side bed pieces R and D, the upright plate A, and the reversible anti-friction sliding jaws o o o. The upright plate A is attached to the slide D in such a way that it may be readily raised or lowered or adjusted in any other direction at pleasure; and may be set with either side facing the lathe head. Of the reversible sliding jaws o o o, which are made of Phosphor Bronze Anti-Friction Metal, not requiring the use of oil, four sets of three in a set, are furnished with each attachment. These are of different form, as shown at X V O U, to adapt them to the various kinds of watch work, and are operated in radial grooves in the upright plate A, by means of the rotating lever L, which moves the three jaws in and out, to and from the center, or opens and closes them in perfect unison. One set of jaws may be withdrawn and another set substituted therefor in a few moments. With each change of the jaws, however, the plate A requires readjustment; but this, too, may be done in a few moments, as follows: Having previously provided yourself with a bit of straight wire or small steel rod, turned to run perfectly true in your lathe, and having fastened this in the chuck in your lathe, loosen the nuts C C so as to give freedom of movement to the plate A; then bring the attachment to proper position on the lathe bed and fasten it there; after which move the sliding jaws inward until they bind lightly on the bit of straight wire held in your chuck, and in this position again tighten the nuts C C. Once adjusted to accurate center in this way no further adjustment, whatever the size of work to be operated upon, is required, until another change of jaws.

In use, the end of the work to be operated upon is placed in an accurate split chuck in the lathe and the chuck tightened on it just sufficiently to hold it in place and to rotate it, the other end being supported in the centered bearing formed by the jaws o o o. In this position the jaws o o o, or such others as for the time may be in use, may be opened and closed as often as desired, and each time will instantly bring the work again to accurate center. See Rest.