| Hood Tooling & Machine LLC Milling, Turning, Welding, EDM, Grinding · ISO 9001 | Malvern, AR | MillingTurningWeldingEDMGrinding | ISO 9001 |
| Horizon Tech Industries Inc Milling, Turning, Swiss, Finishing | Fort Worth, TX | MillingTurningSwissFinishing | - |
| Horst Engineering Milling, Turning · ISO 9001, AS9100 | East Hartford, CT | MillingTurning | ISO 9001, AS9100 |
| Horst Manufacturing Co Inc Milling, Turning | Windham, OH | MillingTurning | - |
| HP Machine & Engineering Inc Milling, Turning, EDM | San Jose, CA | MillingTurningEDM | - |
| HPR Machine Milling, Turning | Vista, CA | MillingTurning | - |
| HR CNC Milling | Clearwater, FL | Milling | - |
| HR Machine Turning, Waterjet, EDM | Dayton, OH | TurningWaterjetEDM | - |
| 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 |
| Hunt Enterprises Milling, Turning, Welding | Santa Ana, CA | MillingTurningWelding | - |
| Hydrafab Northwest, Inc Laser, Bending, Welding | Spokane Valley, WA | LaserBendingWelding | - |
| Hyperformance Products Inc Milling, Turning, Punching, Bending, Welding | Huntington Beach, CA | MillingTurningPunchingBendingWelding | - |
| Icc Machining, LLC Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001 | Alvin, TX | MillingTurningWeldingEDMGrindingAssembly | ISO 9001 |
| Idp TM Inc Milling, Turning, EDM · ISO 9001 | Rockwall, TX | MillingTurningEDM | ISO 9001 |
| IFT Worldwide Milling, Stamping, Finishing | South Bend, IN | MillingStampingFinishing | - |
| Impact Machine LLC Milling, Turning · ISO 9001 | Kaukauna, WI | MillingTurning | ISO 9001 |
| 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 |
| Independent Sheet Metal LLC Punching, Welding | Middletown, OH | PunchingWelding | - |
| Industrial Chrome Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001 | Topeka, KS | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | ISO 9001 |
| Industrial Fabricators Milling, Turning, Bending, Welding, Waterjet | Corpus Christi, TX | MillingTurningBendingWeldingWaterjet | - |
| 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 |
| Infinisys Manufacturing LLC Milling, Turning, EDM | Phoenix, AZ | MillingTurningEDM | - |
| Infiniti Manufacture Milling, Welding, Finishing | Corona, CA | MillingWeldingFinishing | - |
| Infinity Precision Inc Milling, Turning, Waterjet, Bending, Grinding · ISO 9001, AS9100 | Simi Valley, CA | MillingTurningWaterjetBendingGrinding | ISO 9001, AS9100 |
| Infinity Precision Machining LLC Milling, Turning | Buffalo, NY | MillingTurning | - |
| Infocus CNC Machining, Inc Milling, Turning, Swiss · ISO 9001, AS9100 | Fountain Valley, CA | MillingTurningSwiss | ISO 9001, AS9100 |
| Innovated Machining Solutions LLC Milling | Port Huron, MI | Milling | - |
| Innovated Metal Fabrication, Inc Turning, Bending, Laser, Welding | Maplewood, MN | TurningBendingLaserWelding | - |
| Innovation Alley Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Insource Design & Manufacturing Technologies, LLC Milling, Turning, Assembly · ISO 9001, ITAR | Manchester, NH | MillingTurningAssembly | ISO 9001, ITAR |
| Inspirnetics, Inc Milling, Turning | Rancho Cucamonga, CA | MillingTurning | - |
| Integra Cast Milling, Turning, Welding, Casting, Finishing, Assembly · ISO 9001, NADCAP | New Britain, CT | MillingTurningWeldingCastingFinishingAssembly | ISO 9001, NADCAP |
| Integrated Components Inc Milling, Turning | Wichita, KS | MillingTurning | - |
| Integrated Machining Co Milling, Turning, Welding, EDM, Grinding · ISO 9001, ITAR | Albuquerque, NM | MillingTurningWeldingEDMGrinding | ISO 9001, ITAR |
| 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 | - |
| Inter-Precision Mold Inc Milling, Turning, Welding, EDM, Grinding, Assembly | El Paso, TX | MillingTurningWeldingEDMGrindingAssembly | - |
| Interior Metals Laser, Punching, Bending, Welding, Finishing | Staten Island, NY | LaserPunchingBendingWeldingFinishing | - |
| International Hardcoat Grinding, Finishing · ISO 9001, NADCAP | Detroit, MI | GrindingFinishing | ISO 9001, NADCAP |
| Interstate Manufacturing Company, Inc Milling, Welding · ITAR | Agawam, MA | MillingWelding | ITAR |
| Intrepid Machine, Inc Milling, Turning · ISO 9001, AS9100 | Brooksville, FL | MillingTurning | ISO 9001, AS9100 |
| Inventery Precision Milling, Turning, Swiss, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Pasadena, CA | MillingTurningSwissFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| 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 | - |