| Henderson Machine, Inc Milling, Turning, Swiss, Welding, EDM · ITAR | Deerfield Beach, FL | MillingTurningSwissWeldingEDM | ITAR |
| 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 | - |
| Herold Precision Metals, LLC Milling, Laser, Punching, Bending, Welding, Stamping, Finishing, Assembly · ISO 9001, ITAR | White Bear Lake, MN | MillingLaserPunchingBendingWeldingStampingFinishingAssembly | ISO 9001, ITAR |
| Hilton Tool Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100 | Clackamas, OR | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100 |
| Hobart Machined Products Inc Welding, Assembly | Maple Valley, WA | WeldingAssembly | - |
| Hogin Machine, Inc Milling, Turning, Swiss, Waterjet, Bending, Welding | Santa Ana, CA | MillingTurningSwissWaterjetBendingWelding | - |
| Holden on Motorsports, LLC Turning, Laser, Welding, Grinding | Zephyrhills, FL | TurningLaserWeldingGrinding | - |
| Holzman Machine LLC Milling, Turning, Welding · ITAR | Clearwater, FL | MillingTurningWelding | ITAR |
| HTT, Inc Laser, Welding, Stamping, EDM, Grinding, Finishing | Sheboygan, WI | LaserWeldingStampingEDMGrindingFinishing | - |
| Huffman Welding & Machine Inc Milling, Turning, Laser, Waterjet, Bending, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Fort Madison, IA | MillingTurningLaserWaterjetBendingWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Hughes Machine Shop, Inc Milling, Turning, Waterjet, Welding · ISO 9001 | Bogalusa, LA | MillingTurningWaterjetWelding | ISO 9001 |
| Humanetics II of Texas, Inc Milling, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100 | Dallas, TX | MillingLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100 |
| Hunt Enterprises Milling, Turning, Welding | Santa Ana, CA | MillingTurningWelding | - |
| Huntington Plating, Inc Milling, Welding, Grinding, Finishing | Huntington, WV | MillingWeldingGrindingFinishing | - |
| Huntington Steel & Supply Co Bending, Welding | Huntington, WV | BendingWelding | - |
| Hybrid CNC Parts Welding, Metal AM · ISO 9001, AS9100, CMMC | Worcester, MA | WeldingMetal AM | ISO 9001, AS9100, CMMC |
| Hydrafab Northwest, Inc Laser, Bending, Welding | Spokane Valley, WA | LaserBendingWelding | - |
| I Auman Machine Co Inc Milling, Turning, Welding | Lebanon, PA | MillingTurningWelding | - |
| I.p. Automation, Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Grinding · ISO 9001 | Colorado Springs, CO | MillingTurningLaserWaterjetBendingWeldingGrinding | ISO 9001 |
| Icc Machining, LLC Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001 | Alvin, TX | MillingTurningWeldingEDMGrindingAssembly | ISO 9001 |
| Img Companies LLC Milling, Turning, Welding, Finishing · ISO 9001, AS9100 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100 |
| Independent Machine Company Milling, Turning, Laser, Welding, Grinding | Escanaba, MI | MillingTurningLaserWeldingGrinding | - |
| Independent Sheet Metal LLC Punching, Welding | Middletown, OH | PunchingWelding | - |
| Indus Precision Mfg., Inc Milling, Turning, Waterjet, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Congers, NY | MillingTurningWaterjetBendingWeldingGrindingFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Industrial Experimental Technologies, LLC Welding, Stamping · ISO 9001 | Auburn Hills, MI | WeldingStamping | ISO 9001 |
| Industrial Fabricators Milling, Turning, Bending, Welding, Waterjet | Corpus Christi, TX | MillingTurningBendingWeldingWaterjet | - |
| Industrial Manufacturing Specialties, Inc Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100 | Decatur, AL | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100 |
| Industrial Metal Finishing Inc Welding, Finishing · AS9100 | Jamestown, NY | WeldingFinishing | AS9100 |
| Industrial Motions Engineering, Inc Milling, Turning, Welding, Grinding, Finishing, Assembly | Wilmington, MA | MillingTurningWeldingGrindingFinishingAssembly | - |
| Industrial Screen & Maintenance, Inc Milling, Turning, Welding, Casting, Grinding · ISO 9001 | Casper, WY | MillingTurningWeldingCastingGrinding | ISO 9001 |
| Infiniti Manufacture Milling, Welding, Finishing | Corona, CA | MillingWeldingFinishing | - |
| Inland Marine Industries Inc Milling, Turning, Waterjet, Punching, Bending, Welding, Grinding, Finishing · ISO 9001, ITAR | Hayward, CA | MillingTurningWaterjetPunchingBendingWeldingGrindingFinishing | ISO 9001, ITAR |
| Innov8 Manufacturing LLC Milling, Turning, Welding, Grinding · ISO 9001 | Farmington, MI | MillingTurningWeldingGrinding | ISO 9001 |
| Innovated Metal Fabrication, Inc Turning, Bending, Laser, Welding | Maplewood, MN | TurningBendingLaserWelding | - |
| Innovation Alley Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Innovative Manufacturing and Design, LLC Milling, Welding, EDM · ISO 9001, ITAR | Greenville, SC | MillingWeldingEDM | ISO 9001, ITAR |
| InSight Manufacturing Milling, Turning, Welding, Forging, Assembly | Murphys, CA | MillingTurningWeldingForgingAssembly | - |
| Integrity Welding & Fabrication LLC Laser, Waterjet, Welding, Finishing | Colorado Springs, CO | LaserWaterjetWeldingFinishing | - |
| Inter-Precision Mold Inc Milling, Turning, Welding, EDM, Grinding, Assembly | El Paso, TX | MillingTurningWeldingEDMGrindingAssembly | - |
| Interactive Manufacturing, Inc Milling, Turning, Waterjet, Welding, Finishing, Assembly | Central Point, OR | MillingTurningWaterjetWeldingFinishingAssembly | - |
| Interior Metals Laser, Punching, Bending, Welding, Finishing | Staten Island, NY | LaserPunchingBendingWeldingFinishing | - |
| International Precision Manufacturing LLC Milling, Turning, Welding, EDM, Assembly · ISO 9001, AS9100, ISO 13485 | Houston, TX | MillingTurningWeldingEDMAssembly | ISO 9001, AS9100, ISO 13485 |
| Interstate Manufacturing Company, Inc Milling, Welding · ITAR | Agawam, MA | MillingWelding | ITAR |
| IntoMetal Bending, Laser, Welding, Metal AM | Lincoln, NE | BendingLaserWeldingMetal AM | - |
| Iowa Metal Spinners Milling, Turning, Laser, Welding, Stamping · ISO 9001 | Cedar Falls, IA | MillingTurningLaserWeldingStamping | ISO 9001 |
| IPMI Manufacturing & Engineering Milling, Turning, Welding | Buckner, MO | MillingTurningWelding | - |
| IronStrong Metal Fabrication LLC Milling, Bending, Laser, Welding | Lancaster, PA | MillingBendingLaserWelding | - |
| Irwin Automation Inc Milling, Turning, Welding, EDM, Grinding | Greensburg, PA | MillingTurningWeldingEDMGrinding | - |
| Ital-Tech Machined Products, LLC Milling, Turning, Welding, Grinding · ISO 9001, ITAR | Groveland, MA | MillingTurningWeldingGrinding | ISO 9001, ITAR |