Security Locknut Inc. has its beginning in the early 1900’s when the original product was first designed and produced under the name Security Machine Products Company in Cleveland, OH. Quickly recognized as a superior fastening solution, the product was tested and approved by the US Navy for use on its equipment.

With sales and successes beginning to build, it seemed as though the company was poised for significant growth. However, with the collapse of the US economy during the Great Depression and the impact that had on the manufacturing industry, the company ceased operations in the early 1930’s. Emerging by the mid to late 1930’s as the Machinery Products Corporation of Chicago, the Security Locknut was again being produced for its customers.

With the start of World War II, a sweeping change came across America and many manufacturing company’s shifted their production lines to military products based lines to support the war effort. One such company was one of the premiere producers of brass musical instruments, C.G. Conn Ltd. of Elkhart, IN. As a result of the ongoing war effort and an ever increasing need for quality performing products manufactured rapidly, in the early 1940’s C. G. Conn Ltd. purchased the exclusive rights to manufacture the Security Locknut. At this time, the company invested in state-of-the-art machinery to produce its new stable of war products.

One of the many casualties of the war effort, in the late 1940’s, C.G. Conn had difficulty regaining its position in the instruments market and following a 6-month strike, sold the assets of the Security Locknut for capital needs. Subsequently, the company was moved back to Chicago and reorganized under the name Security Locknut Corporation. Known as the locknut that "Stays Put Wherever You Wrench It," the Security Locknut was marketed and sold in a broad range of sizes and styles.

In the early 1950’s, the company took another step in production efficiency by automating the manufacture of its nut bodies. It also introduced a new product known as the Caploc Special, a self-contained locknut that utilized the unique spring steel insert technology in an environmentally secure form. The military’s adoption of the Caploc Special as the standard specified on its T-91 track for U.S. tanks manufactured by Cadillac was a testament to the product’s effectiveness and its ability to withstand the extreme environments to which it would be subjected. Security Locknut also began supplying its locknuts to the U.S. railroad industry for the purpose of keeping railroad tracks across America together.

From 1960 to the mid 1980’s, Security Locknut changed ownership a few times, but never its focus. Improved manufacturing processes and an ever expanding customer base led to steady growth for the company during this period.

As the markets began to change in the late 1980’s and through the 1990’s, the engineering staff at Security Locknut was able to engineer several product improvements and expand its product offering. Leveraging its understanding of the design and function of bolted joints, the company began to provide unique custom solutions to its customers. It was during this time that the Security Locknut became the print specified standard on all U.S. Railroad Trackwork.

Today, the company has continued to maintain its tradition of providing quality, engineered fastening solutions centered around its unique spring steel insert technology. With its ability to continually provide the highest quality, best performing locking fastener systems to what has become a global marketplace, Security Locknut Inc. now supplies the world with "America’s most talented locking fastener systems."