GB795955A - Improvements in or relating to radius grinding attachments for milling cutters or the like - Google Patents

Abstract

795,955. Radius-grinding. HOUGHTON, L. N. Feb. 27, 1956 [Nov. 27, 1954], No. 34437/54. Class 60. An attachment for a grinding machine to permit the radius grinding of a workpiece, such as a milling cutter or lathe tool by rocking the attachment about an axis 31 is provided with a detachable setting bar 28 which has one or more datum surfaces 30 offset from the axis 31 and, with the aid of a gauge block, enables the workpiece to be positioned precisely on the attachment at a spacing from the axis which is consistent with the required grinding of the workpiece when the attachment, without the setting bar, is mounted in the machine. The attachment comprises a base plate 10 pivoted at 13 between side arms 12 which at their upper ends are bored to receive coned bushes 16 for mounting them between the centres of a grinding machine ; screws 15 pass through slotted projections on the arms 12 for securing the latter and plate 10 at the desired relative inclination. The workpiece to be ground is releasably mounted on an arbor 19 slidable in a central slot 18 in the plate 10 and, if it is a milling cutter, is arranged to be retained between successive indexed positions by a spring finger 27 locatable in either of two holes 38, 39 in the plate. The bar 28 has two coaxial pins 29 whereby it may be mounted within the bores of the bushes 16 and, as shown, has a single datum surface 30 spaced from the axis 31. The first step in the setting of a milling cutter on the attachment is to swing the bar 28 through 90 degrees from the position shown so that its datum surface lies above the side face of the cutter mounted on the arbor 19, and then adjusting the relative inclination of the plate 10 and arms 12 until the side face of the cutter contacts a gauge block which is disposed against the surface 30 and is of the necessary thickness, taking into account the spacing of this surface from the axes 31, to produce the required radius ; the next step is to swing the bar 28 to the position shown and adjust the cutter along the slot 18 until its edge face contacts the gauge block on the surface 30. After removal of the bar 28, the attachment, with the cutter securely fixed thereto, is mounted between the centres of a grinding machine for rocking about the axis 31 in contact with a rotating grinding wheel ; the bushes 16 have countersunk recesses for engaging these centres. The grinding wheel rotates about an axis parallel to the axis 31 or at right-angles thereto depending upon whether a convex or concave radius is to be formed. If desired, the bar 28 may have two datum surfaces at right-angles to each other in order to avoid having to rotate it between the two setting steps. A lathe tool may be radiused by fixing it in a vice which is locked at the correct position in the slot 18.