Fig. 48. Adjustable Gage for Inside and Outside Measurements
Fig. 48 shows an inside and an outside adjustable gage for accurate work, used in laying out drill jigs, and in setting tools on lathes, shapers, planers, and milling machines. The outside gage is shown in the side view and in the sectional end view marked Y. At X in the same figure is a sectional end view showing how the gage is constructed for inside work. The top and bottom edges are rounded, so that the diameters of holes may be easily measured.
The gage consists of a stepped block B, mounted so as to slide upon the inclined edge of the block C. There are V-ways upon the upper edge of the latter, and the block B is split and arranged to clamp over the ways by the screw shown at S. All parts of the gage are hardened and the faces of the steps marked A, are ground and finished so that at any position of the slide they are parallel to the base of the block C. The lower split portion of the block is spring-tempered to prevent breaking under the action of the screw, and also to cause it to spring open when loosened. The gage has the advantage that it can be quickly adjusted to any size within its limits, which does away with using blocks. In planing a piece to a given thickness, the gage may be set to that height with great accuracy by means of a micrometer caliper, and then the planer or shaper tool adjusted down to the gage. This method does away with the "cut-and-try" process, and will bring the finishing cut within 0.001 inch of the required size. If the piece being planed, or the opening to be measured, is larger than the extreme limit of the gage, parallels may be used. In fitting bushings into bushing holes, the adjustable gage may be moved out to fit the hole, and then, when the bushing is finished to the diameter given by the gage, as determined by a micrometer caliper, a driving fit is ensured.[[26]]
Radius Gage
Fig. 49. Radius Gage
Fig. 49 shows a radius gage which has proved to be very handy for all such work as rounding corners or grinding tools to a given radius. The blades are of thin steel, and are fastened together at the end by a rivet, thus forming a tool similar to the familiar screw pitch gage. The right-hand corner of each blade is rounded off to the given radius, while the left-hand corner is cut away to the same radius, thus providing an instrument to be used for either convex or concave surfaces. The radius to which each blade is shaped is plainly stamped upon the side.[[27]]
Gage for Grinding Drills
Fig. 50. Gage for Grinding Drills