Granite State Manufacturing

About Granite State Manufacturing

GSM-built systems are on every U.S. Navy submarine in the fleet. For almost 90 years, our team has been engineering and manufacturing the equipment that helps submarines breathe, listen, and communicate. We're a family-owned, AS9100D- and ITAR-registered manufacturer with 175+ employees across two facilities in Manchester and Nashua, New Hampshire. Our capabilities span CNC machining, Navy-certified welding of standard and exotic alloys, fabrication, electro-mechanical assembly, wiring, and testing — from first prototype through full-rate production. Our shops run 30+ machining centers, including 5-axis milling up to 33 ft long and 82 in diameter, and welding capacity up to 35,000 lbs. We serve the defense, medical, security, and industrial markets, with the U.S. Navy as our largest customer. What sets GSM apart: the technical depth to handle complex programs, the compliance rigor our customers require (ISO 9001, AS9100D, ITAR), and a team that takes pride in work that matters.