CHAPTER IV
MISCELLANEOUS MEASURING TOOLS AND GAGES
Among the miscellaneous measuring tools and gages dealt with in this chapter are tools and gages for measuring and comparing tapers, adjustable gages, radius gages, gages for grinding drills, sensitive gages, tools for gaging taper threaded holes, contour gages, etc. Of course, these are offered merely as examples of what can be done in the line of measuring tools for different purposes, and, while having a distinct and direct value to the mechanic, they also have a great indirect value, because they furnish suggestions for the designing and making of tools for similar purposes.
Tool for Measuring Tapers
Fig. 45. Taper Measuring Tool
Fig. 45 shows a tool which has proved very useful. It is a tool for measuring tapers on dowel pins, reamers, drill shanks, or anything to be tapered. Most machinists know that to find the taper of a shank they must use their calipers for one end and reset them for the other end; or else caliper two places, say, three inches apart, and if, for instance, the difference should be 1/16 inch, they must multiply this difference by four to get the taper per foot. With the tool above mentioned, all this trouble in calipering and figuring is saved. Simply place the shank or reamer to be measured between pins A, B, C, and D, and slide H and K together. Then the taper can be read at once on the graduated scale at L. The construction of the tool will be readily understood. The body or base F has a cross piece supporting the two pins A and B. On this slides piece K, which has at its right end the graduated segment. The screw G is fast to piece K, and upon it swivels the pointer E, which carries the two pins C and D. Thus these two pins can be brought into contact with a tapered piece of any diameter within the capacity of the tool, and the swivel screw G allows the pins to adjust themselves to the taper of the work and the pointer E to move to the left or right, showing instantly the taper per foot.
As the pins A and B are 1½ inch apart, which is ⅛ of a foot, and the distance from G to L is 4½ inches, which is three times longer than the distance between A and B, the graduations should be 3/64 inch apart, in order to indicate the taper per foot in eighths of an inch.[[23]]
Taper Gage