| Microform Precision LLC Turning, Bending, Laser, Welding, Waterjet | Sacramento, CA | TurningBendingLaserWeldingWaterjet | - |
| Mid-State Metals Bending, Welding | Orlando, FL | BendingWelding | - |
| Midlake Products & Mfg. Co., Inc Turning, Bending, Laser, Welding, Stamping | Canton, OH | TurningBendingLaserWeldingStamping | - |
| Midwest Machining Solutions LLC Milling, Turning, Waterjet, Welding, Assembly | Saint Louis, MO | MillingTurningWaterjetWeldingAssembly | - |
| Midwest Precision Inc Bending, Laser, Welding, Waterjet · ISO 9001 | Tulsa, OK | BendingLaserWeldingWaterjet | ISO 9001 |
| Midwest Tool Inc Milling, Turning, Welding, EDM, Grinding | Joplin, MO | MillingTurningWeldingEDMGrinding | - |
| Midwest Tool Inc. Milling, Bending, Welding | Chicago, IL | MillingBendingWelding | - |
| Mikron Manufacturing Inc Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Colorado Springs, CO | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Millennium Metalcraft, Inc Milling, Laser, Bending, Welding, Finishing, Assembly · ISO 9001 | Fremont, CA | MillingLaserBendingWeldingFinishingAssembly | ISO 9001 |
| Millwood Metalworks Punching, Bending, Welding | Freeport, MN | PunchingBendingWelding | - |
| Milwaukee Metal Products Co Bending, Welding, Stamping | Milwaukee, WI | BendingWeldingStamping | - |
| 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 |
| MM Industries Tech LLC Laser, Punching, Bending, Welding, Assembly | Stanwood, WA | LaserPunchingBendingWeldingAssembly | - |
| Mofab Inc Milling, Laser, Waterjet, Bending, Welding | Anderson, IN | MillingLaserWaterjetBendingWelding | - |
| Moll Machine Works, LLC Milling, Turning, Welding | Williamson, NY | MillingTurningWelding | - |
| Monarch Valve Corp Milling, Turning, Welding, Grinding, Assembly · ISO 9001 | Aston, PA | MillingTurningWeldingGrindingAssembly | ISO 9001 |
| Mono Engineering Corp Turning, Welding, EDM · ISO 9001 | Chatsworth, CA | TurningWeldingEDM | ISO 9001 |
| Montgomery Dynamics Milling, Turning, Welding · ISO 9001, ITAR | Huntingdon Valley, PA | MillingTurningWelding | ISO 9001, ITAR |
| Morena Welding Inc Welding | San Diego, CA | Welding | - |
| Morrison Berkshire Inc Welding | North Adams, MA | Welding | - |
| Motion Metalworks LLC Laser, Waterjet, Bending, Welding, Finishing | Wrens, GA | LaserWaterjetBendingWeldingFinishing | - |
| MSP Maufacturing Milling, Turning, Bending, Welding, Finishing, Assembly | Bloomington, IN | MillingTurningBendingWeldingFinishingAssembly | - |
| Music City Sheet Metal Bending, Laser, Welding | Nashville, TN | BendingLaserWelding | - |
| Napoleon Machine LLC Milling, Bending, Welding, Forging, Grinding · ISO 9001, ITAR, CMMC | Napoleon, OH | MillingBendingWeldingForgingGrinding | ISO 9001, ITAR, CMMC |
| NCX Concepts LLC Milling, Welding · ITAR | Charlotte, NC | MillingWelding | ITAR |
| Nelgo Manufacturing Co Milling, Turning, Punching, Welding · ISO 9001, AS9100, ITAR | Oceanside, CA | MillingTurningPunchingWelding | ISO 9001, AS9100, ITAR |
| Neosource, Inc. Milling, Welding, Waterjet · ISO 9001, AS9100 | Tulsa, OK | MillingWeldingWaterjet | ISO 9001, AS9100 |
| New Tech Metals Milling, Turning, Laser, Punching, Bending, Welding, Stamping, Finishing, Assembly · ISO 9001, AS9100, ITAR, IATF 16949, CMMC | Green Bay, WI | MillingTurningLaserPunchingBendingWeldingStampingFinishingAssembly | ISO 9001, AS9100, ITAR, IATF 16949, CMMC |
| Nexus Automation Milling, Welding, EDM, Assembly · ISO 9001, ITAR, ISO 13485 | Livermore, CA | MillingWeldingEDMAssembly | ISO 9001, ITAR, ISO 13485 |
| NKP Metals LLC Waterjet, Welding | Chicago, IL | WaterjetWelding | - |
| NMB Manufacturing LLC Milling, Turning, Bending, Welding | Bixby, OK | MillingTurningBendingWelding | - |
| Nocturnal Welding Welding | Camarillo, CA | Welding | - |
| Northern States Metals Bending, Welding, Stamping · ISO 9001 | Youngstown, OH | BendingWeldingStamping | ISO 9001 |
| Northwest Steel Fab, Inc Milling, Punching, Bending, Welding | Deer Park, WA | MillingPunchingBendingWelding | - |
| NRL & Associates Inc Milling, Turning, Bending, Welding, Assembly | Stevensville, MD | MillingTurningBendingWeldingAssembly | - |
| O. W. Landergren, Inc Milling, Laser, Punching, Bending, Welding, Stamping, EDM, Grinding, Finishing | Pittsfield, MA | MillingLaserPunchingBendingWeldingStampingEDMGrindingFinishing | - |
| OGS Industries Turning, Bending, Laser, Welding, Stamping · ISO 9001, AS9100, ITAR, IATF 16949 | Akron, OH | TurningBendingLaserWeldingStamping | ISO 9001, AS9100, ITAR, IATF 16949 |
| Olympic Industries Laser, Welding, Stamping | Cordova, TN | LaserWeldingStamping | - |
| Omega Metals Bending, Welding | Ogden, UT | BendingWelding | - |
| Onodi Tool & Engineering Co Milling, Turning, Welding, Assembly · ISO 9001 | Melvindale, MI | MillingTurningWeldingAssembly | ISO 9001 |
| Oscar's Custom Iron Works Welding | San Antonio, TX | Welding | - |
| Ottenweller Company, Inc. Bending, Laser, Welding · ISO 9001 | Fort Wayne, IN | BendingLaserWelding | ISO 9001 |
| Ozark Steel Llc Milling, Bending, Laser, Welding · ISO 9001 | Tulsa, OK | MillingBendingLaserWelding | ISO 9001 |
| P&M Steel Company Welding | Sioux Falls, SD | Welding | - |
| Pacific Architectural Metals LLC Bending, Laser, Welding | Seattle, WA | BendingLaserWelding | - |
| Palmetto Precision Machining, Inc Milling, Welding, EDM, Grinding · ISO 9001 | Anderson, SC | MillingWeldingEDMGrinding | ISO 9001 |
| Parallax Manufacturing LLC Milling, Turning, Bending, Welding, Stamping, Assembly · NADCAP | Lake Elsinore, CA | MillingTurningBendingWeldingStampingAssembly | NADCAP |
| Pasco Machine Co Waterjet, Welding | Pasco, WA | WaterjetWelding | - |
| Patience Metal Fab Turning, Bending, Welding | Brooklyn Center, MN | TurningBendingWelding | - |