| Hogin Machine, Inc Milling, Turning, Swiss, Waterjet, Bending, Welding | Santa Ana, CA | MillingTurningSwissWaterjetBendingWelding | - |
| HollyFab Turning, Bending, Laser, Welding, Waterjet | Addison, TX | TurningBendingLaserWeldingWaterjet | - |
| 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 |
| Hydrafab Northwest, Inc Laser, Bending, Welding | Spokane Valley, WA | LaserBendingWelding | - |
| I.p. Automation, Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Grinding · ISO 9001 | Colorado Springs, CO | MillingTurningLaserWaterjetBendingWeldingGrinding | ISO 9001 |
| Industrial Sales & Manufacturing, Inc. Milling, Turning, Bending, Laser, Welding · ISO 9001 | Erie, PA | MillingTurningBendingLaserWelding | ISO 9001 |
| Infinity Precision Inc Milling, Turning, Waterjet, Bending, Grinding · ISO 9001, AS9100 | Simi Valley, CA | MillingTurningWaterjetBendingGrinding | ISO 9001, AS9100 |
| Inland Marine Industries Inc Milling, Turning, Waterjet, Punching, Bending, Welding, Grinding, Finishing · ISO 9001, ITAR | Hayward, CA | MillingTurningWaterjetPunchingBendingWeldingGrindingFinishing | ISO 9001, ITAR |
| Innovation Alley Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Integrated Ideas & Technologies Inc Laser, Waterjet, Bending | Coeur D Alene, ID | LaserWaterjetBending | - |
| IntoMetal Bending, Laser, Welding, Metal AM | Lincoln, NE | BendingLaserWeldingMetal AM | - |
| ISCO Manufacturing Solutions Milling, Turning, Waterjet, Bending, Welding, Grinding · ISO 9001, AS9100 | Bend, OR | MillingTurningWaterjetBendingWeldingGrinding | ISO 9001, AS9100 |
| J & A Manufacturing, Inc Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Garland, TX | LaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| J & N Metal Products, LLC Milling, Laser, Bending, Welding, EDM · ISO 9001 | Brazil, IN | MillingLaserBendingWeldingEDM | ISO 9001 |
| J & P Khamken Industries Inc Milling, Turning, Waterjet, Bending, Welding · ISO 9001 | Montgomery, AL | MillingTurningWaterjetBendingWelding | ISO 9001 |
| J Mark Co Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Vista, CA | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| J.i.t. Manufacturing, Inc Milling, Laser, Punching, Bending, Welding, Finishing, Assembly | Cowpens, SC | MillingLaserPunchingBendingWeldingFinishingAssembly | - |
| JC Macelroy Co Inc Milling, Punching, Bending, Welding, Grinding, Assembly | Piscataway, NJ | MillingPunchingBendingWeldingGrindingAssembly | - |
| JC Machine, Inc Milling, Turning, Swiss, Laser, Bending, Welding | Lakeland, FL | MillingTurningSwissLaserBendingWelding | - |
| JD Laser Inc Laser, Bending | Hartford, WI | LaserBending | - |
| JD Machine Milling, Turning, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningBendingWeldingEDM | ISO 9001, AS9100, ITAR, CMMC |
| Jet Speed Metals Bending, Welding | Westbrook, ME | BendingWelding | - |
| Jetfab LLC Milling, Turning, Laser, Waterjet, Punching, Bending, Welding | Lowell, MA | MillingTurningLaserWaterjetPunchingBendingWelding | - |
| Jkeys LLC Laser, Bending, Finishing | Willis, TX | LaserBendingFinishing | - |
| John W. McDougall Co. Bending, Laser, Welding · ISO 9001 | Nashville, TN | BendingLaserWelding | 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 | - |
| Justified Performance LLC Laser, Bending, Welding, Finishing, Assembly · ISO 9001 | Rocklin, CA | LaserBendingWeldingFinishingAssembly | ISO 9001 |
| Kammerer Dynamics Inc Laser, Bending, Welding, Casting, Finishing, Assembly | Kendallville, IN | LaserBendingWeldingCastingFinishingAssembly | - |
| Kaskaskia Tool and Machine, Inc Milling, Turning, Bending, Welding, Stamping, EDM, Grinding · ISO 9001, AS9100 | New Athens, IL | MillingTurningBendingWeldingStampingEDMGrinding | ISO 9001, AS9100 |
| KBM Industries Bending, Welding | Mechanicsburg, PA | BendingWelding | - |
| Kencoa Aerospace LLC Milling, Turning, Waterjet, Punching, Bending, Welding, Stamping · AS9100, ITAR | Eastman, GA | MillingTurningWaterjetPunchingBendingWeldingStamping | AS9100, ITAR |
| Kenney Industries, Inc. Bending, Welding · ISO 9001, NADCAP | Dallas, TX | BendingWelding | ISO 9001, NADCAP |
| Ki Machine Tools & Productions Inc Milling, Turning, Bending, Welding, EDM, Grinding | Loves Park, IL | MillingTurningBendingWeldingEDMGrinding | - |
| Kinney Manufacturing, LLC Bending, Laser, Welding, Metal AM | Lincoln, NE | BendingLaserWeldingMetal AM | - |
| Ko Laser Milling, Turning, Laser, Bending, Welding | Tulsa, OK | MillingTurningLaserBendingWelding | - |
| KSM Industries Inc Bending, Welding, Assembly | Germantown, WI | BendingWeldingAssembly | - |
| L. E. F., Inc Milling, Laser, Bending, Welding, Stamping, Finishing | Tulsa, OK | MillingLaserBendingWeldingStampingFinishing | - |
| Laciny Brothers., Inc. Bending, Welding, Waterjet | St. Louis, MO | BendingWeldingWaterjet | - |
| Lacross Enterprises Inc Turning, Laser, Punching, Bending, Welding | Louisville, KY | TurningLaserPunchingBendingWelding | - |
| Lasasco Inc Punching, Bending, Welding | Boise, ID | PunchingBendingWelding | - |
| Laser Craft Technologies Inc Milling, Turning, Laser, Punching, Bending, Welding, Assembly · ISO 9001 | Gainesville, GA | MillingTurningLaserPunchingBendingWeldingAssembly | ISO 9001 |
| Laser Cutting Co Milling, Laser, Bending, Welding, Grinding, Finishing · ISO 9001 | Harrison Township, MI | MillingLaserBendingWeldingGrindingFinishing | ISO 9001 |
| Laserworx Mfg Laser, Bending, Welding, Stamping · AS9100, ITAR | Oxnard, CA | LaserBendingWeldingStamping | AS9100, ITAR |
| Latitude Corp Milling, Waterjet, Punching, Bending, Welding, Stamping, Grinding, Finishing · AS9100 | Verona, WI | MillingWaterjetPunchingBendingWeldingStampingGrindingFinishing | AS9100 |
| Laystrom Manufacturing Company Bending, Laser, Welding | Chicago, IL | BendingLaserWelding | - |
| Lee Precision Machine Shop Inc. Milling, Turning, Bending, Welding, EDM · ISO 9001, ITAR | Athens, AL | MillingTurningBendingWeldingEDM | ISO 9001, ITAR |
| Lehi Sheet Metal Turning, Laser, Punching, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100, ITAR | Westborough, MA | TurningLaserPunchingBendingWeldingGrindingFinishing | ISO 9001, AS9100, ITAR |
| Lewis Precision & CNC Inc Milling, Turning, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100 | Theodore, AL | MillingTurningBendingWeldingGrindingFinishing | ISO 9001, AS9100 |