Over the past century and a half, manufacturing has made considerable progress. New machine tools, high-performance cutting tools, modern manufacturing processes, and creative management tools have combined to enable today's industries to make parts faster and more precisely than ever before. Although workholding methods have also advanced considerably, the basic principles of clamping and locating are still the same.
The first manufactured products were made one at a time. Early artisans started with little more than raw materials and a rough idea of the finished product. They produced each product piece by piece, making each part individually and fitting the parts into the finished product. This process took time. Moreover, the quality and consistency of products varied from one artisan to the next. As they worked, early manufacturing pioneers realized the need for better methods and developed new ideas.
Eventually, they found the secret of mass production: standardized parts. Standard parts not only speeded production, they also ensured the interchangeability of parts. The idea may be obvious today, but in its time, pioneered by Eli Whitney, it was revolutionary.
These standard parts were the key to enabling less-skilled workers to replicate the skill of the craftsman on a repetitive basis. The original method of achieving consistent part configuration was the template. Templates for layout, sawing, and filing permitted each worker to make parts to a standard design. While early templates were crude, they at least gave skilled workers a standard form to follow for the part. Building on the template idea, workers constructed other guides and workholders to make their jobs easier and the results more predictable. These guides and workholders were the ancestors of today's jigs and fixtures.
Yesterday's workholders had the same two basic functions as today's workholders: securely holding and accurately locating a workpiece. Early jigs and fixtures may have lacked modern refinements, but they followed many of the same principles as today's workholder designs.
As machine tools have evolved, workholding has advanced to keep pace. More powerful and more precise machines are of little value if the work cannot be held securely so the capabilities of the machine can be utilized. Consequently, new concepts and new devices have been developed to locate, support and clamp the part in place while it is being machined. Workholding concepts have also advanced to improve the utilization of the new machine tools.
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This page contains information originally published in the Jig & Fixture Handbook, 3rd Edition, Copyright 2016, Carr Lane Manufacturing Co., St. Louis, Mo.