| Helical Machining, Inc Milling, Turning, Welding, EDM, Grinding, Finishing, Assembly | Sun Valley, CA | MillingTurningWeldingEDMGrindingFinishingAssembly | - |
| Henry's Metal Polishing, Inc Turning, Bending, Welding, Grinding, Finishing · ISO 9001 | S El Monte, CA | TurningBendingWeldingGrindingFinishing | ISO 9001 |
| Heritage Fabrication Inc Milling, Turning, Laser, Punching, Bending, Welding, Finishing | Sedalia, MO | MillingTurningLaserPunchingBendingWeldingFinishing | - |
| HNDO Precision Milling, Laser, Finishing | Santa Rosa, CA | MillingLaserFinishing | - |
| Holz Enterprises, Inc Milling, Turning, Finishing · AS9100, ITAR | Bellingham, WA | MillingTurningFinishing | AS9100, ITAR |
| Horizon Tech Industries Inc Milling, Turning, Swiss, Finishing | Fort Worth, TX | MillingTurningSwissFinishing | - |
| HTT, Inc Laser, Welding, Stamping, EDM, Grinding, Finishing | Sheboygan, WI | LaserWeldingStampingEDMGrindingFinishing | - |
| Hubbell Machine Co Inc Milling, Turning, Finishing · ISO 9001, AS9100 | Paso Robles, CA | MillingTurningFinishing | ISO 9001, AS9100 |
| Huffman Welding & Machine Inc Milling, Turning, Laser, Waterjet, Bending, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Fort Madison, IA | MillingTurningLaserWaterjetBendingWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Humanetics II of Texas, Inc Milling, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100 | Dallas, TX | MillingLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100 |
| IFT Worldwide Milling, Stamping, Finishing | South Bend, IN | MillingStampingFinishing | - |
| Imperial Carbide Inc Milling, Turning, Welding, Stamping, EDM, Grinding, Finishing · ISO 9001 | Meadville, PA | MillingTurningWeldingStampingEDMGrindingFinishing | ISO 9001 |
| Impulse Precision Manufacturing Milling, Stamping, Finishing · ISO 9001, ITAR, NADCAP | Wilsonville, OR | MillingStampingFinishing | ISO 9001, ITAR, NADCAP |
| Industrial Chrome Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001 | Topeka, KS | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | ISO 9001 |
| Industrial Metal Finishing Inc Welding, Finishing · AS9100 | Jamestown, NY | WeldingFinishing | AS9100 |
| Industrial Motions Engineering, Inc Milling, Turning, Welding, Grinding, Finishing, Assembly | Wilmington, MA | MillingTurningWeldingGrindingFinishingAssembly | - |
| Infiniti Manufacture Milling, Welding, Finishing | Corona, CA | MillingWeldingFinishing | - |
| Integra Cast Milling, Turning, Welding, Casting, Finishing, Assembly · ISO 9001, NADCAP | New Britain, CT | MillingTurningWeldingCastingFinishingAssembly | ISO 9001, NADCAP |
| Integrity Manufacturing Co EDM, Finishing · ISO 9001 | Colorado Springs, CO | EDMFinishing | ISO 9001 |
| Integrity Welding & Fabrication LLC Laser, Waterjet, Welding, Finishing | Colorado Springs, CO | LaserWaterjetWeldingFinishing | - |
| Interior Metals Laser, Punching, Bending, Welding, Finishing | Staten Island, NY | LaserPunchingBendingWeldingFinishing | - |
| International Hardcoat Grinding, Finishing · ISO 9001, NADCAP | Detroit, MI | GrindingFinishing | ISO 9001, NADCAP |
| Inventery Precision Milling, Turning, Swiss, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Pasadena, CA | MillingTurningSwissFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| J & L Precision Manufacturing LLC Bending, Welding, Stamping, Finishing, Assembly · ISO 9001 | Brooklyn Heights, OH | BendingWeldingStampingFinishingAssembly | ISO 9001 |
| J A-Co Machine Works, LLC Milling, Turning, Swiss, Welding, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP, ISO 13485 | Scotts Valley, CA | MillingTurningSwissWeldingFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP, ISO 13485 |
| J.i.t. Manufacturing, Inc Milling, Laser, Punching, Bending, Welding, Finishing, Assembly | Cowpens, SC | MillingLaserPunchingBendingWeldingFinishingAssembly | - |
| J&D Custom Finishing | Holden, MO | Finishing | - |
| J&M Machining Milling, Turning, Welding, Casting, Finishing · ISO 9001 | Norton Shores, MI | MillingTurningWeldingCastingFinishing | ISO 9001 |
| Jaco Engineering Milling, Turning, Bending, Welding, EDM, Grinding, Finishing, Assembly · NADCAP | Anaheim, CA | MillingTurningBendingWeldingEDMGrindingFinishingAssembly | NADCAP |
| Jaffa Precision Engineering Inc Milling, Turning, Swiss, Welding, Grinding, Finishing · ISO 9001 | Riverside, CA | MillingTurningSwissWeldingGrindingFinishing | ISO 9001 |
| Jars Inc Milling, Waterjet, Bending, Welding, EDM, Grinding, Finishing | San Fernando, CA | MillingWaterjetBendingWeldingEDMGrindingFinishing | - |
| JBC Machine Inc Milling, Turning, Welding, Finishing | Hortonville, WI | MillingTurningWeldingFinishing | - |
| Jem Custom Products, Inc Milling, Finishing | Wauconda, IL | MillingFinishing | - |
| Jenkins Machine Inc Milling, Turning, EDM, Grinding, Finishing | Bethlehem, PA | MillingTurningEDMGrindingFinishing | - |
| Jet Helseth Manufacturing Inc Turning, EDM, Finishing, Assembly · ISO 9001, ITAR | Deland, FL | TurningEDMFinishingAssembly | ISO 9001, ITAR |
| JG Innovations, Inc Finishing | Janesville, WI | Finishing | - |
| JJR Engineering & Fabrication Inc Milling, Turning, Bending, Welding, Stamping, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Woodinville, WA | MillingTurningBendingWeldingStampingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| Jkeys LLC Laser, Bending, Finishing | Willis, TX | LaserBendingFinishing | - |
| JMR Machining LLC Milling, Turning, Casting, Finishing | Athens, TX | MillingTurningCastingFinishing | - |
| John J Steuby Co Milling, Turning, Swiss, Welding, Stamping, Casting, EDM, Finishing · ISO 9001, ITAR | Hazelwood, MO | MillingTurningSwissWeldingStampingCastingEDMFinishing | ISO 9001, ITAR |
| Johnson Brass & Machine Foundry Inc Casting, Finishing | Saukville, WI | CastingFinishing | - |
| Jolar Machine Shop Milling, Grinding, Finishing · ISO 9001 | Dickson City, PA | MillingGrindingFinishing | ISO 9001 |
| Jones Metal, Inc Milling, Laser, Waterjet, Bending, Welding, Finishing, Assembly | Mankato, MN | MillingLaserWaterjetBendingWeldingFinishingAssembly | - |
| Just One More Part, LLC Bending, Welding, Finishing | Pottstown, PA | BendingWeldingFinishing | - |
| Kad Models and Prototypes Inc Milling, Finishing, Assembly | East Randolph, VT | MillingFinishingAssembly | - |
| Kammerer Dynamics Inc Laser, Bending, Welding, Casting, Finishing, Assembly | Kendallville, IN | LaserBendingWeldingCastingFinishingAssembly | - |
| Kaydek Machining, Inc Milling, Turning, Finishing · ISO 9001, AS9100 | San Jose, CA | MillingTurningFinishing | ISO 9001, AS9100 |
| Kennley Corp Milling, Turning, Grinding, Finishing | North Chesterfield, VA | MillingTurningGrindingFinishing | - |
| Kilgore Manufacturing Co Inc Milling, Swiss, Bending, Welding, EDM, Finishing, Assembly · ISO 9001, ITAR | Columbia City, IN | MillingSwissBendingWeldingEDMFinishingAssembly | ISO 9001, ITAR |
| Kinross Fab & Machine Inc Milling, Turning, Laser, Welding, Grinding, Finishing | Kincheloe, MI | MillingTurningLaserWeldingGrindingFinishing | - |