science · 29 July 1890 · 134 years ago
In 1890, Laroy Sunderland Starrett received a U.S. patent for his micrometer screw guage (No. 433,311), which is the form still familiar and indispensible to any machinist or person measuring small objects in a physics lab. Since 1881, he had worked to improve the micrometers then existing. His design had a vernier scale, a smaller head, a locking device and a small knob extending from the barrel to enable quick rotation while closing the initial gap to the inserted object being measured. By 1899, his micrometer was available in a one-inch size for $6.50, including a leather case. He took out many other patents for the tools he invented or improved, and established a substantial tool manufacturing business.
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