Tool presetting device with tapered air spindle mount

Abstract

A tool holder has on its lower end an inverted, frusto-conically shaped bearing surface which is releasably seated coaxially in a correspondingly shaped opening which is formed in the upper surface of a stationary support. Intermediate its ends the bore wall which defines the frusto-conically shaped opening in the support has therein a shallow, circumferential recess, which is connected through a port in the support with a supply of fluid under pressure. In use the lower end of the tool holder is held in the opening in the support solely by gravity; and a tool, which is mounted in the upper end of the holder, is positioned adjacent a conventional gauging device which can measure tooth height and tool runout. Fluid under pressure is supplied to the recess in an amount sufficient to cause the tool holder to be elevated slightly without breaking the seal between the recess and the frusto-conically shaped bearing surface on the tool holder, whereby the tool holder can then be readily rotated manually. In a second embodiment two such supports are mounted in coaxially spaced, confronting relation, rotatably to support a specially shaped spindle, which has thereon a pair of opposed, axially spaced, frusto-conically shaped bearing surfaces that are rotatably seated in said supports coaxially thereof. Each support has the circumferential recess in its bore connected to a supply of fluid under pressure, so that when fluid is supplied to the recesses the associated supports tend to shift slightly axially away from each other to reduce the resistance to rotation of the shaft relative to the supports.