To simplify fabrication of an integral hub piece, the opening between the
upper and lower female cones in this hub has sufficient width or radial
dimension to allow access to both cones from one side of the hub with the
cutting tool. A cutting tool is used which has a width smaller than the
opening between the cones. Preferably, the tool has a width which is
about equal to or smaller than an angular dimension through this opening
which is defined by extending surfaces of the upper and lower female
cones. If this limitation is satisfied, both cones can be created with a
single machine set up operating from one side of the integrated hub.