SignatureGMMCO Company History

Erik Junkunc

Stephen Junkunc II founded GMMCO in 1918, realizing a dream of owning his own machine shop. Stephen progressed into manufacturing metal stampings for casket hardware. With the outbreak of World War II, GMMCO converted the shop for the war effort and began manufacturing various aircraft parts, including B-29 hydraulic spools on behalf of Ford Motor Company, who was sub-contracting work from engine maker Pratt & Whitney.

GMMCO’s quality and service was so dependable that Pratt & Whitney asked GMMCO to manufacture a critical fuel nozzle seal for JT3 turbofan and J57 turbojet – the world’s first jet engine to develop 10,000 lbs. of thrust and the power-plant for the B-52 Stratofortress.

Since then, GMMCO went on to co-design many other types of unique fuel nozzle seals for Pratt & Whitney, including our signature “knife-edge seal”.  GMMCO seals and related parts are being used on many military, commercial, and aero-derivative turbine engines.  GMMCO is now under the leadership of Erik Junkunc, fourth generation of the Junkunc family.

Originally just an automatic screw machine shop, GMMCO now combines conventional machining with sophisticated CNC equipment and manufacturing techniques, machining various precision machined components for many industries.  The long standing tradition of caring for our customer’s needs continues to be a guiding principle passed down through the generations.


Innovative Solutions to Industry Challenges

Double Knife Edge

Today’s ultra-competitive markets call for innovative manufacturing solutions. We believe in partnering along with our customers to offer truly unique alternative solutions to fit their individual needs.   GMMCO continues to invest in state of the art machining and inspections technologies to offer a versatile and wide range of delivery capabilities.  We will strive to continue to invest and develop even more capabilities to better serve your needs.


Service & Delivery

Smart Scope

We are dedicated to on-time delivery performance and a satisfying customer experience.   Our staff cares deeply about your complete satisfaction as our final goal.


GMMCO Additional Services

Precision Machined Parts