Size Block and Gage Method
Another method which can at times be employed for accurately locating a jig-plate in different positions on an angle-plate, is shown in [Fig. 29]. The angle-plate is, of course, set at right angles to the spindle and depth gages and size blocks are used for measuring directly the amount of adjustment. Both the angle-plate and work should have finished surfaces on two sides at right angles to each other, from which measurements can be taken. After the first hole has been bored, the plate is adjusted the required distance both horizontally and vertically, by using micrometer depth gages, which should preferably be clamped to the angle-plate. If the capacity of the gages is exceeded, measurements may be taken by using standard size blocks in conjunction with the depth gages.
Fig. 29. Locating Work from Edges of Angle-Plate
by means of Depth Gages and Size Blocks
It is frequently necessary to bore holes in cast jig-plates or machine parts, which either have irregularly shaped or unfinished edges. A good method of locating such work is illustrated in [Fig. 30]. The part to be bored is attached to an auxiliary plate A which should have parallel sides and at least two edges which are straight and at right angles to each other. This auxiliary plate with the work, is clamped against an accurate angle-plate B, which should be set square with the axis of the machine spindle. A parallel strip is bolted to the angle-plate and the inner edge is set square with the machine table. After the first hole is bored, the work is located for boring the other to the edge of the auxiliary plate, and horizontal measurements y between the parallel and the plate. These measurements, if quite large, might be taken with micrometer gages, whereas, for comparatively small adjustments, size blocks might be more convenient.