Patent ID: 7269989
Filing Date: 2007-09-18
Classification: B21J,Y10T

Abstract:
1. A method of using a tool to form an orifice through a workpiece having first and second generally planar surfaces spaced apart along a longitudinal axis with a volume of material therebetween, the method comprising: preventing lateral movements of a workpiece with respect to a support surface; extending a tool having a tool body comprising an elongated member having a circular cross-section defining a generally circular perimeter into the volume of material between the first and second generally planar surfaces of the workpiece to form first and second impressions in sequence, the first and second impressions being spaced apart about the longitudinal axis so that the first impression forms a first orifice wall extending between the first and second generally planar surfaces at an acute angle with respect to the first generally planar surface; and penetrating through the first generally planar surface to the other generally planar surface; wherein, the preventing lateral movements comprises orientating the tool having a tool axis oblique to one of the generally planar surfaces, the tool having a pilot work surface spaced from a main work surface, the pilot work surface facing the first generally planar surface of the workpiece and being disposed on a first virtual plane, the pilot work surface comprising an area bounded by a first arcuate portion of the perimeter of the tool body and a first chord connecting the first arcuate portion; the extending comprises penetrating into the first generally planar surface with the pilot work surface and the main work surface such that the area penetrated by the pilot work surface has an area less than the area penetrated by the main work surface; and the penetrating comprises projecting a transition work surface into the first generally planar surface of the workpiece, the transition work surface extending through the tool axis at a first oblique angle with respect to a second virtual plane contiguous to the pilot work surface.