| JC Machine, Inc Milling, Turning, Swiss, Laser, Bending, Welding | Lakeland, FL | MillingTurningSwissLaserBendingWelding | - |
| Jones & Lockhart Fabrication LLC Bending, Welding | St. Louis, MO | BendingWelding | - |
| JP Metal Fabrication, Inc. Milling, Bending, Laser, Welding | Santa Clara, CA | MillingBendingLaserWelding | - |
| Just One More Part, LLC Bending, Welding, Finishing | Pottstown, PA | BendingWeldingFinishing | - |
| K & E Plastics Inc Milling, Turning, Swiss, Bending · ISO 9001, ITAR | Bennington, VT | MillingTurningSwissBending | ISO 9001, ITAR |
| Kammerer Dynamics Inc Laser, Bending, Welding, Casting, Finishing, Assembly | Kendallville, IN | LaserBendingWeldingCastingFinishingAssembly | - |
| KB Sheetmetal Fabrication, Inc Turning, Bending, Welding, Finishing · ISO 9001 | Fountain Valley, CA | TurningBendingWeldingFinishing | ISO 9001 |
| Kilgore Manufacturing Co Inc Milling, Swiss, Bending, Welding, EDM, Finishing, Assembly · ISO 9001, ITAR | Columbia City, IN | MillingSwissBendingWeldingEDMFinishingAssembly | ISO 9001, ITAR |
| Lakecraft, Inc Turning, Bending, Welding, Grinding, Finishing | Port Clinton, OH | TurningBendingWeldingGrindingFinishing | - |
| Laser Craft Technologies Inc Milling, Turning, Laser, Punching, Bending, Welding, Assembly · ISO 9001 | Gainesville, GA | MillingTurningLaserPunchingBendingWeldingAssembly | ISO 9001 |
| Laser Metal Fabrication Laser, Bending, Welding, Assembly | Twin Falls, ID | LaserBendingWeldingAssembly | - |
| Laserform & Machine Inc Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Columbia, SC | TurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Lathrom Manufacturing Inc Milling, Turning, Bending, Grinding · ISO 9001, ITAR | Wichita, KS | MillingTurningBendingGrinding | ISO 9001, ITAR |
| Laystrom Manufacturing Company Bending, Laser, Welding | Chicago, IL | BendingLaserWelding | - |
| Liberty Hill Company Milling, Turning, Swiss, Laser, Waterjet, Bending, EDM · ISO 9001, AS9100, ITAR | Huntington, WV | MillingTurningSwissLaserWaterjetBendingEDM | ISO 9001, AS9100, ITAR |
| Lima Sheet Metal Machine and Mfg., Inc Turning, Bending, Welding, Grinding | Lima, OH | TurningBendingWeldingGrinding | - |
| LJ Fabricators, Inc. Bending, Laser, Welding · ISO 9001 | Rockford, IL | BendingLaserWelding | ISO 9001 |
| Lomar Machine & Tool Co Milling, Turning, Laser, Bending, Welding, Casting, EDM, Grinding, Finishing · ISO 9001 | Horton, MI | MillingTurningLaserBendingWeldingCastingEDMGrindingFinishing | ISO 9001 |
| M & M Sheet Metal, Inc Milling, Laser, Bending, Welding, Forging · ISO 9001, ITAR, CMMC | Williamsport, PA | MillingLaserBendingWeldingForging | ISO 9001, ITAR, CMMC |
| M 7 Technologies Bending, Welding · ISO 9001 | Youngstown, OH | BendingWelding | ISO 9001 |
| M.a. Metal Co., Inc Laser, Bending, Welding, Stamping, Assembly · ISO 9001 | Columbus, IN | LaserBendingWeldingStampingAssembly | ISO 9001 |
| M&M Metals Inc. Bending, Laser, Welding | San Antonio, TX | BendingLaserWelding | - |
| Majestic Metals by Fathom Manufacturing Milling, Turning, Bending, Laser, Welding, Waterjet, EDM, Casting, Metal AM · ISO 9001, AS9100, ITAR, ISO 13485 | Denver, CO | MillingTurningBendingLaserWeldingWaterjetEDMCastingMetal AM | ISO 9001, AS9100, ITAR, ISO 13485 |
| Massie Mfg Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Finishing · ITAR | Baraga, MI | MillingTurningLaserWaterjetBendingWeldingFinishing | ITAR |
| Master Machine, Inc Milling, Turning, Bending, Casting · ISO 9001 | Minneapolis, MN | MillingTurningBendingCasting | ISO 9001 |
| Master Tool & Manufacturing Inc Turning, Bending, Welding, EDM, Grinding · ISO 9001, ITAR | Hiawatha, IA | TurningBendingWeldingEDMGrinding | ISO 9001, ITAR |
| Melting Point Metalworks LLC Laser, Bending, Welding | Brownsburg, IN | LaserBendingWelding | - |
| Mercury Aircraft Inc Milling, Laser, Punching, Bending, Welding, Stamping, Assembly · ISO 9001, AS9100, ITAR | Hammondsport, NY | MillingLaserPunchingBendingWeldingStampingAssembly | ISO 9001, AS9100, ITAR |
| Metal Components LLC Turning, Waterjet, Bending, Welding, Finishing, Assembly · ISO 9001 | Grand Rapids, MI | TurningWaterjetBendingWeldingFinishingAssembly | ISO 9001 |
| Metal Products Inc Milling, Turning, Waterjet, Bending, Welding, EDM, Grinding | Appleton, WI | MillingTurningWaterjetBendingWeldingEDMGrinding | - |
| Metalcraft Inc Bending, Laser, Welding | Boise, ID | BendingLaserWelding | - |
| MetalMania Bending, Laser, Welding | Brooklyn, NY | BendingLaserWelding | - |
| Metaltech Inc Laser, Bending, Welding, Assembly · AS9100 | Auburn, WA | LaserBendingWeldingAssembly | AS9100 |
| Microform Precision LLC Turning, Bending, Laser, Welding, Waterjet | Sacramento, CA | TurningBendingLaserWeldingWaterjet | - |
| Mid America Steel Inc Milling, Bending, Welding, Casting | Fargo, ND | MillingBendingWeldingCasting | - |
| Midlake Products & Mfg. Co., Inc Turning, Bending, Laser, Welding, Stamping | Canton, OH | TurningBendingLaserWeldingStamping | - |
| Midwest Industrial Metal Fabrication Inc Milling, Turning, Punching, Bending, Welding, Stamping, Finishing | Huntington, IN | MillingTurningPunchingBendingWeldingStampingFinishing | - |
| Midwest Metal Fabrications Milling, Turning, Bending, Laser, Welding · ISO 9001, AS9100 | Tallmadge, OH | MillingTurningBendingLaserWelding | ISO 9001, AS9100 |
| Midwest Precision Inc Bending, Laser, Welding, Waterjet · ISO 9001 | Tulsa, OK | BendingLaserWeldingWaterjet | ISO 9001 |
| Millennium Metalcraft, Inc Milling, Laser, Bending, Welding, Finishing, Assembly · ISO 9001 | Fremont, CA | MillingLaserBendingWeldingFinishingAssembly | ISO 9001 |
| Mission Critical Solutions LLC Milling, Punching, Bending, Welding | Alum Bank, PA | MillingPunchingBendingWelding | - |
| MJM Manufacturing Inc Milling, Laser, Punching, Bending, Welding, Stamping · ISO 9001, AS9100, ITAR | Miami Lakes, FL | MillingLaserPunchingBendingWeldingStamping | ISO 9001, AS9100, ITAR |
| Moultrie Tool & Manufacturing Co Inc Milling, Turning, Bending, Welding, EDM, Stamping · ISO 9001 | Memphis, TN | MillingTurningBendingWeldingEDMStamping | ISO 9001 |
| MRW Fabrication LLC Bending, Welding | Independence, MO | BendingWelding | - |
| MST Manufacturing LLC Milling, Turning, Bending, Welding, Assembly · ISO 9001, AS9100, ITAR, CMMC | Claremore, OK | MillingTurningBendingWeldingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Ohio Metal Fabricating Inc Turning, Bending, Laser, Welding, Stamping · AS9100 | Dayton, OH | TurningBendingLaserWeldingStamping | AS9100 |
| Olympic Tool Company Milling, Turning, Waterjet, Bending, Welding, EDM, Grinding, Finishing, Assembly | Bayville, NJ | MillingTurningWaterjetBendingWeldingEDMGrindingFinishingAssembly | - |
| Pacific Maritime Industries Corp Milling, Turning, Laser, Waterjet, Punching, Bending, Welding · ISO 9001 | San Diego, CA | MillingTurningLaserWaterjetPunchingBendingWelding | ISO 9001 |
| Pascetti Steel Design, Inc. Bending, Welding | Albuquerque, NM | BendingWelding | - |
| PBZ Manufacturing Laser, Bending, Welding, Finishing · ISO 9001 | Lititz, PA | LaserBendingWeldingFinishing | ISO 9001 |