| Magnum Machine Inc Milling, Turning, Welding, Finishing · ITAR | Raymond, NH | MillingTurningWeldingFinishing | ITAR |
| Magnum Machining LLC Milling, Turning, Finishing | Richmond, IL | MillingTurningFinishing | - |
| Magnum Steel Works Milling, Turning, Waterjet, Bending, Welding | Mount Vernon, IL | MillingTurningWaterjetBendingWelding | - |
| Mah Tooling Co Milling, Turning | Hickory Hills, IL | MillingTurning | - |
| Malone Industrial Machine, L.L.C Milling, Turning, Laser, Bending, Welding | Deer Park, TX | MillingTurningLaserBendingWelding | - |
| Malux Machine LLC Milling, Turning, Welding, Grinding | Stratford, CT | MillingTurningWeldingGrinding | - |
| Manda Machine Co Milling, Turning, Laser, Welding, Waterjet, EDM · ISO 9001, AS9100 | Dallas, TX | MillingTurningLaserWeldingWaterjetEDM | ISO 9001, AS9100 |
| Manufacture.us Milling, Turning, Swiss, Laser, Finishing, Assembly | Doral, FL | MillingTurningSwissLaserFinishingAssembly | - |
| Manufacturing Solutions LLC Milling, Turning, Welding, Finishing | Tulsa, OK | MillingTurningWeldingFinishing | - |
| Manufacturing Standard, LLC Milling, Turning, Swiss, Stamping, Casting · ISO 9001, AS9100, IATF 16949 | Poway, CA | MillingTurningSwissStampingCasting | ISO 9001, AS9100, IATF 16949 |
| Manutek Mfg LLC Milling, Turning, Waterjet · ITAR | Estacada, OR | MillingTurningWaterjet | ITAR |
| Marinette Machine LLC Turning, Welding, Grinding, Finishing | Marinette, WI | TurningWeldingGrindingFinishing | - |
| Marion Manufacturing Milling, Turning, Welding, Stamping, EDM · AS9100 | West Terre Haute, IN | MillingTurningWeldingStampingEDM | AS9100 |
| Marion Manufacturing Co Inc Milling, Turning, Laser, Stamping, EDM | Cheshire, CT | MillingTurningLaserStampingEDM | - |
| Marion Mold & Tool Inc Milling, Turning, Waterjet, EDM, Grinding · ISO 9001, AS9100 | Marion, VA | MillingTurningWaterjetEDMGrinding | ISO 9001, AS9100 |
| Marion Precision Tool, Inc Milling, Turning, Waterjet, Bending, Welding, Grinding · ISO 9001 | Ocala, FL | MillingTurningWaterjetBendingWeldingGrinding | ISO 9001 |
| Maritech Machine Inc Milling, Turning, Waterjet, Welding, Grinding, Finishing · ISO 9001, AS9100 | Panama City, FL | MillingTurningWaterjetWeldingGrindingFinishing | ISO 9001, AS9100 |
| Mark One Metal Works Turning, Bending, Welding | Sparks, NV | TurningBendingWelding | - |
| Mars Engineering Milling, Turning, Waterjet, EDM, Grinding, Finishing, Assembly | San Leandro, CA | MillingTurningWaterjetEDMGrindingFinishingAssembly | - |
| Marshall Precision Machining, Inc Milling, Turning · ISO 9001 | Sanger, TX | MillingTurning | ISO 9001 |
| Martin's Metal Fabrication & Welding, Inc Milling, Turning, Laser, Waterjet, Bending, Welding | Vacaville, CA | MillingTurningLaserWaterjetBendingWelding | - |
| Marton Precision MF Milling, Turning, Waterjet, Welding, EDM, Finishing · ISO 9001, AS9100, ITAR | Fullerton, CA | MillingTurningWaterjetWeldingEDMFinishing | ISO 9001, AS9100, ITAR |
| Marvel Manufacturing Milling, Turning, Swiss, Welding, EDM, Grinding, Finishing | Lewiston, ID | MillingTurningSwissWeldingEDMGrindingFinishing | - |
| Maryland Greater Tool & Manufacturing Milling, Turning, Waterjet, Welding, Grinding, Finishing | Mountain Lake Park, MD | MillingTurningWaterjetWeldingGrindingFinishing | - |
| Marzilli Machine Co Milling, Turning, Welding · ISO 9001, ITAR | Seekonk, MA | MillingTurningWelding | ISO 9001, ITAR |
| Mason Dixon Fabrication LLC Milling, Turning, Welding, Assembly | Hanover, PA | MillingTurningWeldingAssembly | - |
| Master Machine LLC Milling, Turning, Welding · ISO 9001 | Chattanooga, TN | MillingTurningWelding | ISO 9001 |
| Masters Machine Company Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR | Bristol, ME | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR |
| Masterson Industries, Inc Turning, Grinding, Finishing | Taylor, TX | TurningGrindingFinishing | - |
| Mat-Tech Machining Milling, Turning, Welding | Milwaukee, WI | MillingTurningWelding | - |
| Maumee Pattern Co Milling, Turning, Casting, EDM · ITAR, CMMC | Toledo, OH | MillingTurningCastingEDM | ITAR, CMMC |
| Max Machine Milling, Turning, Laser, Waterjet, Welding, Grinding, Finishing · ISO 9001 | Elizabethtown, PA | MillingTurningLaserWaterjetWeldingGrindingFinishing | ISO 9001 |
| Max Machining LLC Milling, Turning, Laser, Bending · ITAR, CMMC | Telford, PA | MillingTurningLaserBending | ITAR, CMMC |
| MBK Machine Corp Milling, Turning, Laser, EDM, Grinding · ITAR | Mead, CO | MillingTurningLaserEDMGrinding | ITAR |
| McClintic R-D-M, Inc Milling, Turning, Waterjet, Welding | Albuquerque, NM | MillingTurningWaterjetWelding | - |
| McCormick Industries Inc Milling, Turning, Swiss, Welding, Grinding, Finishing, Assembly · ISO 9001 | Appleton, WI | MillingTurningSwissWeldingGrindingFinishingAssembly | ISO 9001 |
| McGinley Manufacturing Milling, Turning, Swiss, Welding, EDM · ISO 13485 | Glenrock, WY | MillingTurningSwissWeldingEDM | ISO 13485 |
| McKenzie Machining Inc Milling, Turning, EDM, Grinding · ISO 9001, AS9100, ITAR | San Jose, CA | MillingTurningEDMGrinding | ISO 9001, AS9100, ITAR |
| McKiney Manufacturing Milling, Turning, Laser, Waterjet, Bending, Welding | Mitchell, NE | MillingTurningLaserWaterjetBendingWelding | - |
| McNeil Industries Inc Milling, Turning, Welding, Stamping, Grinding, Assembly · ISO 9001, AS9100 | Painesville, OH | MillingTurningWeldingStampingGrindingAssembly | ISO 9001, AS9100 |
| Mdi Manufacturing Inc Milling, Turning, Welding, Grinding, Assembly · ISO 9001 | Lakewood, NJ | MillingTurningWeldingGrindingAssembly | ISO 9001 |
| Mean Machine LLC Milling, Turning, EDM | Logan, UT | MillingTurningEDM | - |
| Mechfi Designs LLC Milling, Turning, Finishing | Westminster, CO | MillingTurningFinishing | - |
| Mega Machine Shop Inc Milling, Turning, Welding | Tumwater, WA | MillingTurningWelding | - |
| Memac Industries Inc Milling, Turning, Welding, Grinding | Lancaster, OH | MillingTurningWeldingGrinding | - |
| Mennie's Machine Co Milling, Turning, Welding, Grinding · IATF 16949 | Mark, IL | MillingTurningWeldingGrinding | IATF 16949 |
| Menze Precision Machining, LLC Milling, Turning, Bending, Welding, EDM, Grinding, Finishing | Winter Haven, FL | MillingTurningBendingWeldingEDMGrindingFinishing | - |
| Mercer Machine Company, Inc Milling, Turning, EDM · AS9100 | Camby, IN | MillingTurningEDM | AS9100 |
| Mercury Machine Works LLC Milling, Turning, Laser, Finishing · ISO 9001, ITAR | Spring, TX | MillingTurningLaserFinishing | ISO 9001, ITAR |
| Mercury Machining Co Milling, Turning, Welding, Grinding | Pensacola, FL | MillingTurningWeldingGrinding | - |