Mr. Popenoe, age 76, holds US patents for the direct tension indicating bolts and also has a global patent pending for SmartBolts®. He invented the instrumented bolts when he saw a Popular Mechanics article for a tension-indicating bolt with a glass window that shattered when it achieved the right tension.  Chuck knew he could improve on that concept and the SmartBolt was born. SmartBolts® employ a unique re-usable color-changing indicator that allows the user to directly read the tension on the fastener. The indicator is based on the most accurate known principle for fastener tension measurement - actual fastener elongation under load. 

Ms. Dennis and her colleagues began researching local inventors with interesting workspaces over two years ago through INCA, Inventors Network of the Capital Area.  She sought submissions from the group on their workspaces and was immediately attracted to Chuck's description of his basement workshop.  Ms. Dennis, archivist Alison Oswald, and Mr. Popenoe then began a series of collaborative visits that ultimately included a workshop on documentation techniques for historians, an oral history interview, and a video session in Chuck’s basement workshop.  "Documenting living inventors," Ms. Dennis says, "gives us the opportunity to capture information about skills, work methods, and tacit knowledge, key elements of the invention process usually not found in the historic record."

She plans to continue working with Mr. Popenoe to document how his bolts are manufactured at a new facility in Westminster, Maryland. All of the Lemelson Center's work is recorded and will be deposited in the Archives Center at the National Museum of American History. The Lemelson Center hopes that one day Mr. Popenoe will consider donating his records to the museum’s collections.