Jig and fixture design; a treatise covering the principles of jig and fixture design, the important constructional details, and many different types ... devices used in interchangeable manufacture

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...B, the work is held tight without springing it; and by tightening the nut C the clamp is held in place by the bunter and the work is securely supported. When reloading the fixture, the clamp is brought out of the way by means of the handle D. In Fig. 71 is shown a small clamping device used when drilling the rivet holes through the beading A and the plate B. The steel bracket C is fastened by screws to the side of the fixture. The front face of the clamp bracket is used as a stop for the plate and the beading, and the clamp D with a small hole drilled in one end is fitted loosely in the milled slot in the bracket. The set-screw is located a little higher than the hole in the clamp and by a few turns of the screw the clamp is brought down against the work and forces the beading up against the stop ready to be drilled. Spring bunters are often used in designing fixtures where adjustable supports are necessary, and the form of bunter shown in Fig. 72 has proved very efficient. The bunter A and the binder B fit freely in the holes in the casting. The bunter is slightly tapered and a tapered flat is milled on one side of the binder. When the fixture is loaded the spring D forces the bunter up against the work, and by means of the cam C the binder is pulled outward and holds the bunter firmly in place. The double taper on both bunter and binder makes it impossible to press the bunter downward away from the work. Conclusion.--When designing clamping devices, as few operating screws or handles should be used as will accomplish the desired result, for it takes considerable time to turn a screw one or two revolutions four or five thousand times a day, which is an average number of operations for many jigs. Making the screw with a double or triple thread is sometimes ...