This is Part #1 of Combination Squares, Ames, Chaplin, Standard Tool.
Starting with the earliest metal manufactured combination square in the USA, is the Nathan Ames one. It was patented July 6, 1852 (#9.089). Apparently, it was not initially produced, but it was first shown in the September 22, 1855, Scientific American (page 16). Soon after G. Holiday began to manufacture it. By the end of the 1850’s Brown & Sharpe took over manufacture of it. They were made in various sizes. The example shown is a 12” one (as measured by the rule sticking out). This one was made by Holliday. The long reference edge is 8 ½” long by ½” thick. The 45-degree edge is 6” on the outside, 5 3/8” on the inside, and ½” thick. Although there are no moving parts, it is still a combination square because it does more than one thing. Like a regular square it can make a 90-degree angle. It also can do a 45-degree angle. Using the two 45 degree surfaces you can find the center of a round. (There is an article on how to make a wooden one in Fine Wood Working Magazine)
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Next is the Orril Chaplin design. Patented one May 8, 1866 (#54,504). Originally made by Chaplin, it has a movable rule. On one side is a square reference side, measuring 6” long by ¾” thick. Opposite this is a pair of 45-degree sides, 3 ¼” long. This can accommodate standard rules 1” wide by .092 thick, 12” or longer. A groove is not needed as this square clamps on the outside edge. By 1881 the Standard Tool Company was producing it. Below are examples of each. The original Chaplin on the left and the Standard Tool on the right. The Chaplin is more ornate, with lots of “hooks” sticking out. From the first picture they look pretty similar, however, when turning them over you will see that the Standard Tool improvement was an additional reference edge at the bottom of the 45-degree angle. In addition, the thickness was reduced to ½” in this area. Why? Well, the original design allowed either a 90-degree angle or it could be used for finding the center of a round. It was not useful for 45-degree angles. The Standard Tool design with the extra reference edge allows a 45-degree angle. Standard Tool sold out to Starrett in 1905 and not produced after that.
Chaplin 1.jpgChaplin 2.jpg
Part #2 will cover Starrett.
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