| H & M Machine Inc Milling, Turning, Welding, Stamping, EDM, Grinding, Finishing | Greendale, WI | MillingTurningWeldingStampingEDMGrindingFinishing | - |
| H&H Metal Fabrication Bending, Welding | St. Louis, MO | BendingWelding | - |
| Hadley Precision Milling, Turning, Welding | Baton Rouge, LA | MillingTurningWelding | - |
| Haig Precision Manufacturing Corp Milling, Turning, Laser, Punching, Bending, Welding, Stamping, EDM, Grinding, Finishing, Assembly | San Jose, CA | MillingTurningLaserPunchingBendingWeldingStampingEDMGrindingFinishingAssembly | - |
| Halfab, Inc Milling, Turning, Welding, Finishing | Livermore, CA | MillingTurningWeldingFinishing | - |
| Hallmark Metals Inc Milling, Turning, Laser, Punching, Welding, Stamping, Finishing · ISO 9001, ITAR, NADCAP | Glendora, CA | MillingTurningLaserPunchingWeldingStampingFinishing | ISO 9001, ITAR, NADCAP |
| Hamill Manufacturing Co Milling, Turning, Welding, EDM · ISO 9001, ITAR | Trafford, PA | MillingTurningWeldingEDM | ISO 9001, ITAR |
| Hammer MetalWerks Bending, Laser, Welding | Indianapolis, IN | BendingLaserWelding | - |
| Hanset Stainless Inc Welding | Portland, OR | Welding | - |
| Harcon Precision Metals, Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Finishing | San Diego, CA | MillingTurningLaserWaterjetPunchingBendingWeldingFinishing | - |
| Hards Fabrication & Welding, Inc Milling, Turning, Waterjet, Bending, Welding | Seneca, PA | MillingTurningWaterjetBendingWelding | - |
| Harris Machine Co Milling, Bending, Welding, Finishing, Assembly | Oakes, ND | MillingBendingWeldingFinishingAssembly | - |
| Harrison Electropolishing, L.P Welding, Finishing · ISO 9001 | Houston, TX | WeldingFinishing | ISO 9001 |
| Harshco, L.L.C Milling, Turning, Swiss, Laser, Waterjet, Bending, Welding · ISO 9001, AS9100 | Scottsdale, AZ | MillingTurningSwissLaserWaterjetBendingWelding | ISO 9001, AS9100 |
| Harvey Brothers Inc Bending, Welding | Cincinnati, OH | BendingWelding | - |
| Harvey Vogel Manufacturing Co Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Stamping, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Saint Paul, MN | MillingTurningLaserWaterjetPunchingBendingWeldingStampingEDMGrindingFinishingAssembly | ISO 9001, AS9100 |
| Hastreiter Industries Corp Milling, Turning, Laser, Bending, Welding, Grinding, Finishing · ISO 9001, ITAR | Marshfield, WI | MillingTurningLaserBendingWeldingGrindingFinishing | ISO 9001, ITAR |
| Hayes Manufacturing Company, Incorporated Milling, Welding | Pineville, LA | MillingWelding | - |
| Heighten America, Inc Milling, Turning, Welding, Assembly · ISO 9001 | Oakdale, CA | MillingTurningWeldingAssembly | ISO 9001 |
| Heiton Manufacturing LLC Milling, Turning, Laser, Welding | Forney, TX | MillingTurningLaserWelding | - |
| Helanbak, LLC Milling, Turning, Waterjet, Welding | Columbia, MS | MillingTurningWaterjetWelding | - |
| Hennemuth Metal Fabricators Bending, Welding, Waterjet | Oakdale, PA | BendingWeldingWaterjet | - |
| Henry's Metal Polishing, Inc Turning, Bending, Welding, Grinding, Finishing · ISO 9001 | S El Monte, CA | TurningBendingWeldingGrindingFinishing | ISO 9001 |
| Herker Industries Inc Milling, Turning, Swiss, Welding, Assembly · ISO 9001 | Menomonee Falls, WI | MillingTurningSwissWeldingAssembly | ISO 9001 |
| High Star Corp Milling, Turning, Bending, Welding, Stamping, Grinding, Finishing · ISO 9001 | Westland, MI | MillingTurningBendingWeldingStampingGrindingFinishing | ISO 9001 |
| High Steel Structures LLC Welding | Lancaster, PA | Welding | - |
| High Tech Machine II Co Limited Milling, Turning, Welding, EDM | Houston, TX | MillingTurningWeldingEDM | - |
| Hill Aerosystems Inc Milling, Turning, Waterjet, Punching, Bending, Welding, Stamping, EDM, Assembly · AS9100 | Enumclaw, WA | MillingTurningWaterjetPunchingBendingWeldingStampingEDMAssembly | AS9100 |
| Hilton Tool Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100 | Clackamas, OR | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100 |
| Hitech Metalfab Inc Bending, Welding · ISO 9001 | Santa Clara, CA | BendingWelding | ISO 9001 |
| HMF Corporation Bending, Laser, Welding | Anaheim, CA | BendingLaserWelding | - |
| Hogin Machine, Inc Milling, Turning, Swiss, Waterjet, Bending, Welding | Santa Ana, CA | MillingTurningSwissWaterjetBendingWelding | - |
| Holbrook Laser, Welding | Franklin, IN | LaserWelding | - |
| Holzman Machine LLC Milling, Turning, Welding · ITAR | Clearwater, FL | MillingTurningWelding | ITAR |
| Hood Tooling & Machine LLC Milling, Turning, Welding, EDM, Grinding · ISO 9001 | Malvern, AR | MillingTurningWeldingEDMGrinding | ISO 9001 |
| Houston Foundry Manufacturing, L.L.C Milling, Welding, Casting · ISO 9001, AS9100 | Houston, TX | MillingWeldingCasting | ISO 9001, AS9100 |
| Hughes Machine Shop, Inc Milling, Turning, Waterjet, Welding · ISO 9001 | Bogalusa, LA | MillingTurningWaterjetWelding | ISO 9001 |
| 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 |
| Industrial Chrome Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001 | Topeka, KS | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | ISO 9001 |
| Industrial Experimental Technologies, LLC Welding, Stamping · ISO 9001 | Auburn Hills, MI | WeldingStamping | 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 | - |
| Industrial Sales & Manufacturing, Inc. Milling, Turning, Bending, Laser, Welding · ISO 9001 | Erie, PA | MillingTurningBendingLaserWelding | ISO 9001 |
| Industrial Screen & Maintenance, Inc Milling, Turning, Welding, Casting, Grinding · ISO 9001 | Casper, WY | MillingTurningWeldingCastingGrinding | ISO 9001 |
| Infiniti Manufacture Milling, Welding, Finishing | Corona, CA | MillingWeldingFinishing | - |
| Inno-Tec Welding & Fabrication LLC Welding | Springfield, OH | Welding | - |