| Henderson Machine, Inc Milling, Turning, Swiss, Welding, EDM · ITAR | Deerfield Beach, FL | MillingTurningSwissWeldingEDM | ITAR |
| Hennig Milling · ISO 9001, AS9100 | Rockford, IL | Milling | ISO 9001, AS9100 |
| 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 |
| Hexagon Machine & Manufacturing LLC Milling, Assembly · ISO 9001, AS9100 | Longmont, CO | MillingAssembly | ISO 9001, AS9100 |
| Hi Performance Machine & Metals, Inc Milling, Turning, Waterjet, EDM · ISO 9001 | Lakeside, CA | MillingTurningWaterjetEDM | ISO 9001 |
| Hi Tech Machining & Engineering LLC Milling, Turning, EDM, Grinding | Tucson, AZ | MillingTurningEDMGrinding | - |
| High Altitude Manufacturing Global Inc Milling, Turning, Swiss, Laser, Finishing | Molalla, OR | MillingTurningSwissLaserFinishing | - |
| High Speed CNC Milling, Turning · ISO 9001, AS9100 | Santa Clara, CA | MillingTurning | ISO 9001, AS9100 |
| Highline Tool Inc Milling, Turning, Swiss, Grinding | Hillsboro, OR | MillingTurningSwissGrinding | - |
| Hiler Industries Milling, Turning, Casting, EDM · ISO 9001 | La Porte, IN | MillingTurningCastingEDM | ISO 9001 |
| Hillside Engineering, Inc Milling, Turning, Grinding, Assembly | Danvers, MA | MillingTurningGrindingAssembly | - |
| Hilton Tool Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100 | Clackamas, OR | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100 |
| HM Quality Machining Inc Milling, Turning, Laser, Waterjet, Grinding | Ontario, CA | MillingTurningLaserWaterjetGrinding | - |
| HNDO Precision Milling, Laser, Finishing | Santa Rosa, CA | MillingLaserFinishing | - |
| Hofacker Precision Machining LLC Milling, Turning, Casting · ISO 9001 | Clayton, OH | MillingTurningCasting | ISO 9001 |
| Hogin Machine, Inc Milling, Turning, Swiss, Waterjet, Bending, Welding | Santa Ana, CA | MillingTurningSwissWaterjetBendingWelding | - |
| Holz Enterprises, Inc Milling, Turning, Finishing · AS9100, ITAR | Bellingham, WA | MillingTurningFinishing | AS9100, ITAR |
| Holzman Machine LLC Milling, Turning, Welding · ITAR | Clearwater, FL | MillingTurningWelding | ITAR |
| Homebase Machining LLC Milling, Turning | Meridian, ID | MillingTurning | - |
| Honeycutt Manufacturing Inc Milling, Turning, Swiss, Stamping, Grinding, Finishing | Mukilteo, WA | MillingTurningSwissStampingGrindingFinishing | - |
| Horst Engineering Milling, Turning · ISO 9001, AS9100 | East Hartford, CT | MillingTurning | ISO 9001, AS9100 |
| HP Machine & Engineering Inc Milling, Turning, EDM | San Jose, CA | MillingTurningEDM | - |
| HPR Machine Milling, Turning | Vista, CA | MillingTurning | - |
| HR CNC Milling | Clearwater, FL | Milling | - |
| Hub Pattern Corp Milling, Turning, Waterjet, EDM, Grinding, Assembly | Roanoke, VA | MillingTurningWaterjetEDMGrindingAssembly | - |
| 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 Design & Manufacturing Inc Milling, Turning, Swiss, EDM, Grinding · AS9100 | Arab, AL | MillingTurningSwissEDMGrinding | AS9100 |
| Hunt Enterprises Milling, Turning, Welding | Santa Ana, CA | MillingTurningWelding | - |
| Huntington Plating, Inc Milling, Welding, Grinding, Finishing | Huntington, WV | MillingWeldingGrindingFinishing | - |
| Hy-Speed Machining, Inc Milling, Turning, EDM | Grants Pass, OR | MillingTurningEDM | - |
| 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 |
| Ibs Machine & Manufacturing LLC Milling, Turning | Ocala, FL | MillingTurning | - |
| Icc Machining, LLC Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001 | Alvin, TX | MillingTurningWeldingEDMGrindingAssembly | ISO 9001 |
| Icon Machine Co Milling, Turning, Casting · ISO 9001, AS9100 | Irving, TX | MillingTurningCasting | ISO 9001, AS9100 |
| Ifl Manufacturing Inc Milling, Stamping | Wauconda, IL | MillingStamping | - |
| Img Companies LLC Milling, Turning, Welding, Finishing · ISO 9001, AS9100 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100 |
| Impact Machine LLC Milling, Turning · ISO 9001 | Kaukauna, WI | MillingTurning | ISO 9001 |
| Incremental Machine Milling, Bending | Baltimore, MD | MillingBending | - |
| Independent Machine Company Milling, Turning, Laser, Welding, Grinding | Escanaba, MI | MillingTurningLaserWeldingGrinding | - |
| 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 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 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 |
| Industrial Tool, Inc Milling · ISO 9001, ITAR | Anoka, MN | Milling | ISO 9001, ITAR |
| Infinisys Manufacturing LLC Milling, Turning, EDM | Phoenix, AZ | MillingTurningEDM | - |