| OMS Precision Machining Milling, Turning, Swiss, Casting, Grinding, Finishing · ISO 9001, ITAR | Oshkosh, WI | MillingTurningSwissCastingGrindingFinishing | ISO 9001, ITAR |
| Orlando Metal Fabrication Inc Milling, Waterjet, Punching, Bending, Welding, Finishing · ISO 9001, AS9100 | Orlando, FL | MillingWaterjetPunchingBendingWeldingFinishing | ISO 9001, AS9100 |
| Air-Way Manufacturing Company Finishing · ISO 9001 | Olivet, MI | Finishing | ISO 9001 |
| David Packard Company, Inc Milling, Turning, Swiss, Grinding, Finishing, Assembly · ISO 9001, ITAR | Oxford, MA | MillingTurningSwissGrindingFinishingAssembly | ISO 9001, ITAR |
| Demco Products Milling, Turning, Swiss, Finishing, Assembly · ISO 9001 | Oak Lawn, IL | MillingTurningSwissFinishingAssembly | ISO 9001 |
| Fox Worx Precision LLC Milling, Finishing · ISO 9001, ITAR | Ontario, OR | MillingFinishing | ISO 9001, ITAR |
| General Plug and Manufacturing Co Milling, Casting, EDM, Grinding, Finishing · ISO 9001 | Oberlin, OH | MillingCastingEDMGrindingFinishing | ISO 9001 |
| KW Products, Inc Milling, Turning, Finishing · ISO 9001, AS9100 | Oldsmar, FL | MillingTurningFinishing | ISO 9001, AS9100 |
| MMG Corp Milling, Turning, Finishing, Assembly · ISO 9001 | Ontario, CA | MillingTurningFinishingAssembly | ISO 9001 |
| The Will-Burt Company Finishing · ISO 9001 | Orrville, OH | Finishing | ISO 9001 |
| Ankeny Automation, LLC Milling, Laser, Welding, Grinding, Finishing | Omaha, NE | MillingLaserWeldingGrindingFinishing | - |
| Critical Components-Oil & Gas Milling, Turning, Welding, Metal AM, Finishing | Oklahoma City, OK | MillingTurningWeldingMetal AMFinishing | - |
| Harris Machine Co Milling, Bending, Welding, Finishing, Assembly | Oakes, ND | MillingBendingWeldingFinishingAssembly | - |
| Korzan Enterprises Inc Milling, Turning, Waterjet, Welding, EDM, Grinding, Finishing | Orchard Park, NY | MillingTurningWaterjetWeldingEDMGrindingFinishing | - |
| Nebraska Machine Products, Inc Turning, Welding, Grinding, Finishing | Omaha, NE | TurningWeldingGrindingFinishing | - |
| NTO Designs Milling, Turning, Laser, Welding, Finishing | Ormond Beach, FL | MillingTurningLaserWeldingFinishing | - |
| Odyssey Machining Milling, Finishing · ISO 9001, ITAR | San Jose, CA | MillingFinishing | ISO 9001, ITAR |
| Omanson Precision Engineering, Inc Milling, Finishing · ISO 9001, AS9100 | Chino, CA | MillingFinishing | ISO 9001, AS9100 |
| Omni Precision Components Milling, Turning, Finishing · ISO 9001 | Holland, MI | MillingTurningFinishing | ISO 9001 |
| One Source Manufacturing Technology LLC Milling, Turning, Welding, Grinding, Finishing · ISO 9001, AS9100 | Leander, TX | MillingTurningWeldingGrindingFinishing | ISO 9001, AS9100 |
| Opti-Forms Inc Stamping, EDM, Finishing · ISO 9001, ITAR | Temecula, CA | StampingEDMFinishing | ISO 9001, ITAR |
| Orion Precision Industries, Inc Swiss, Bending, Finishing · ISO 9001, ITAR | Somerset, NJ | SwissBendingFinishing | ISO 9001, ITAR |
| Ortiz Tool, LLC Milling, Turning, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP | Windsor, CT | MillingTurningFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP |
| Pierce Steel Fabricators & Machining, Inc Punching, Bending, Welding, Finishing | Olean, NY | PunchingBendingWeldingFinishing | - |
| Precisioncore Manufacturing LLC Milling, Laser, Bending, Finishing · CMMC | Orange City, FL | MillingLaserBendingFinishing | CMMC |
| Square One Coating Systems LLC Finishing · NADCAP | Oriskany, NY | Finishing | NADCAP |
| American Machining Inc Milling, Turning, Welding, Grinding, Finishing · ISO 9001 | Ottawa, IL | MillingTurningWeldingGrindingFinishing | ISO 9001 |
| D & H Industries Inc Milling, Turning, Laser, Bending, Welding, Stamping, Grinding, Finishing · ISO 9001, ITAR | Oconomowoc, WI | MillingTurningLaserBendingWeldingStampingGrindingFinishing | ISO 9001, ITAR |
| Hartman Enterprises Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, AS9100, ITAR | Oneida, NY | MillingTurningSwissGrindingFinishing | ISO 9001, AS9100, ITAR |
| M & R Engineering Milling, Turning, Swiss, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP | Orange, CA | MillingTurningSwissFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP |
| Swissturn/usa, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR, CMMC | Oxford, MA | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR, CMMC |
| United Machining Service Inc Milling, Turning, Welding, Stamping, Finishing, Assembly · ISO 9001 | Orlando, FL | MillingTurningWeldingStampingFinishingAssembly | ISO 9001 |
| 110 Metalworks Inc Milling, Turning, Laser, Bending, Welding, Finishing · ISO 9001, AS9100, ITAR | Liverpool, NY | MillingTurningLaserBendingWeldingFinishing | ISO 9001, AS9100, ITAR |
| 4-M Precision Industries Inc Milling, Turning, Laser, Bending, Welding, Stamping, Finishing · ISO 9001 | Auburn, NY | MillingTurningLaserBendingWeldingStampingFinishing | ISO 9001 |
| A.m.i. Engineering Co LLC Milling, Turning, Finishing · ISO 9001, ITAR | Santa Ana, CA | MillingTurningFinishing | ISO 9001, ITAR |
| AAT Omega, LLC Milling, Turning, Laser, Punching, Bending, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP | Keystone Heights, FL | MillingTurningLaserPunchingBendingWeldingEDMGrindingFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP |
| Able Craft Fabrications, Inc Milling, Turning, Finishing, Assembly · ISO 9001 | Hopkins, MN | MillingTurningFinishingAssembly | ISO 9001 |
| Abston Machine Shop Inc Milling, Turning, Finishing · ISO 9001, ITAR | Taft, TN | MillingTurningFinishing | ISO 9001, ITAR |
| Advanced Fabrication Technology Laser, Punching, Welding, Finishing, Assembly · ISO 9001 | Hayward, CA | LaserPunchingWeldingFinishingAssembly | ISO 9001 |
| Advanced Machining & Tooling, LLC Milling, Turning, Welding, Stamping, EDM, Grinding, Finishing · ISO 9001 | Salisbury, NC | MillingTurningWeldingStampingEDMGrindingFinishing | ISO 9001 |
| Advanced Plating Technologies Welding, Finishing · ISO 9001, ITAR, ISO 13485 | Milwaukee, WI | WeldingFinishing | ISO 9001, ITAR, ISO 13485 |
| Aero Tech Manufactuting Inc Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | North Salt Lake, UT | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Aeroparts Fabricating & Machining Inc Milling, Punching, Bending, Finishing · ISO 9001, AS9100, NADCAP | Nicktown, PA | MillingPunchingBendingFinishing | ISO 9001, AS9100, NADCAP |
| Alanson Mfg L.L.C Turning, Finishing · ISO 9001, ITAR | Chicago, IL | TurningFinishing | ISO 9001, ITAR |
| ALC Engineered Solutions Company Milling, Turning, Swiss, EDM, Finishing · ISO 9001 | Lockwood, MO | MillingTurningSwissEDMFinishing | ISO 9001 |
| Alcaro & Alcaro Plating Co Inc Welding, Stamping, Finishing · ISO 9001 | Montclair, NJ | WeldingStampingFinishing | ISO 9001 |
| All Materials Manufacturing Co LLC Milling, Turning, Swiss, Finishing · ISO 9001, AS9100, ITAR | Riverside, CA | MillingTurningSwissFinishing | ISO 9001, AS9100, ITAR |
| Alloyed Solutions LLC Laser, Bending, Welding, Finishing · ISO 9001 | Price, UT | LaserBendingWeldingFinishing | ISO 9001 |
| Alpha Omega Machining Inc Milling, Turning, Welding, EDM, Finishing · ISO 9001 | Painesville, OH | MillingTurningWeldingEDMFinishing | ISO 9001 |
| Alziebler Incorporated Milling, Turning, Welding, Grinding, Finishing · ISO 9001, AS9100, ITAR, NADCAP | Arleta, CA | MillingTurningWeldingGrindingFinishing | ISO 9001, AS9100, ITAR, NADCAP |