| Lindor Tool, Inc Milling, Turning, Welding, Casting, Grinding | Saint Croix Falls, WI | MillingTurningWeldingCastingGrinding | - |
| Lindsay Machine Works, Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Grinding | Independence, MO | MillingTurningLaserWaterjetBendingWeldingGrinding | - |
| Linita Design & Mfg. Corp Turning, Welding, Assembly | Lackawanna, NY | TurningWeldingAssembly | - |
| LLB Metal Fabrication Limited Liability Company Turning, Laser, Waterjet, Welding | Honolulu, HI | TurningLaserWaterjetWelding | - |
| LNP Machining Milling, Turning, Welding, Finishing · ISO 9001, AS9100, ITAR, ISO 13485 | San Jose, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100, ITAR, ISO 13485 |
| Logan Machine Co Milling, Turning, Bending, Welding | Akron, OH | MillingTurningBendingWelding | - |
| Lorraine Machine Inc Turning, Welding · ISO 9001 | Greenville, SC | TurningWelding | ISO 9001 |
| Ltts Machine LLC Milling, Turning · ISO 9001, AS9100, ITAR | Fort Worth, TX | MillingTurning | ISO 9001, AS9100, ITAR |
| Luna's Sheet Metal Inc Milling, Turning, Bending, Laser, Welding | Santa Clara, CA | MillingTurningBendingLaserWelding | - |
| Luso Machine NJ, LLC Milling, Turning, Welding, EDM · ISO 9001 | Newark, NJ | MillingTurningWeldingEDM | ISO 9001 |
| LX3 Tooling Milling, Turning, Laser, Welding, Grinding · CMMC | Aledo, TX | MillingTurningLaserWeldingGrinding | CMMC |
| Lynchburg Machining, LLC Milling, Turning, Waterjet, Bending, Welding, EDM · ISO 9001 | Lynchburg, VA | MillingTurningWaterjetBendingWeldingEDM | ISO 9001 |
| M & B Machine, Inc Milling, Turning, Swiss, Welding · ISO 9001, AS9100, CMMC | Carlisle, PA | MillingTurningSwissWelding | ISO 9001, AS9100, CMMC |
| M & S Machining Inc Milling, Turning, Bending, Welding, EDM, Assembly · ISO 9001, AS9100, ITAR | Winchester, KY | MillingTurningBendingWeldingEDMAssembly | ISO 9001, AS9100, ITAR |
| M's Machines Milling, Turning, Welding | Monona, IA | MillingTurningWelding | - |
| M&M Machining, Inc Milling, Turning, Welding, Finishing | Ventura, CA | MillingTurningWeldingFinishing | - |
| Mac Machine Company Milling, Turning, Welding, EDM, Grinding · AS9100, ITAR, NADCAP, CMMC | Baltimore, MD | MillingTurningWeldingEDMGrinding | AS9100, ITAR, NADCAP, CMMC |
| Mac Smith Corp Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, Grinding | Gardena, CA | MillingTurningLaserWaterjetBendingWeldingStampingGrinding | - |
| Machine Craft Northwest Inc Milling, Turning, Welding | Lebanon, OR | MillingTurningWelding | - |
| Machine Specialties, LLC Milling, Turning, Swiss, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Whitsett, NC | MillingTurningSwissWeldingEDMGrindingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| Machine Time Inc Milling, Turning, Bending, Welding · ISO 9001, AS9100 | Nicholasville, KY | MillingTurningBendingWelding | ISO 9001, AS9100 |
| Machine-Tech Services, L.L.C Milling, Turning, Welding | Broussard, LA | MillingTurningWelding | - |
| Machined Products Co Turning, Welding · ISO 9001 | Lancaster, PA | TurningWelding | ISO 9001 |
| Machineworks Manufacturing Milling, Turning, Laser, Bending, Welding, Finishing · ISO 9001, AS9100, ITAR | Northridge, CA | MillingTurningLaserBendingWeldingFinishing | ISO 9001, AS9100, ITAR |
| Machining Systems Corporation Milling, Turning, Welding, Grinding, Finishing · ISO 9001 | Crestwood, IL | MillingTurningWeldingGrindingFinishing | ISO 9001 |
| Machining Tech Milling, Turning, Waterjet, Welding, Stamping, EDM, Grinding | Hazle Township, PA | MillingTurningWaterjetWeldingStampingEDMGrinding | - |
| Machinists Inc Milling, Turning, Laser, Welding, EDM, Grinding · ISO 9001, ITAR | Seattle, WA | MillingTurningLaserWeldingEDMGrinding | ISO 9001, ITAR |
| Magna Tool Inc Milling, Turning, Welding · AS9100 | Cypress, CA | MillingTurningWelding | AS9100 |
| Magnum Machine Inc Milling, Turning, Welding, Finishing · ITAR | Raymond, NH | MillingTurningWeldingFinishing | ITAR |
| 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 |
| Major Tool & Machine Milling, Turning, Welding · ISO 9001, AS9100, NADCAP | Indianapolis, IN | MillingTurningWelding | ISO 9001, AS9100, NADCAP |
| 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 | - |
| Manufacture Design Innovation, Inc Milling, Turning, Welding | Gilberts, IL | MillingTurningWelding | - |
| Manufacturing Solutions LLC Milling, Turning, Welding, Finishing | Tulsa, OK | MillingTurningWeldingFinishing | - |
| 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 | - |
| Marton Precision MF Milling, Turning, Waterjet, Welding, EDM, Finishing · ISO 9001, AS9100, ITAR | Fullerton, CA | MillingTurningWaterjetWeldingEDMFinishing | ISO 9001, AS9100, ITAR |
| Marx Digital Manufacturing Inc Milling, Turning, Welding, Assembly | Santa Clara, CA | MillingTurningWeldingAssembly | - |
| Maryland Greater Tool & Manufacturing Milling, Turning, Waterjet, Welding, Grinding, Finishing | Mountain Lake Park, MD | MillingTurningWaterjetWeldingGrindingFinishing | - |
| Mason Dixon Fabrication LLC Milling, Turning, Welding, Assembly | Hanover, PA | MillingTurningWeldingAssembly | - |
| Massie Mfg Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Finishing · ITAR | Baraga, MI | MillingTurningLaserWaterjetBendingWeldingFinishing | ITAR |
| Mat-Tech Machining Milling, Turning, Welding | Milwaukee, WI | MillingTurningWelding | - |
| Maumee Valley Fabricators Turning, Welding | Toledo, OH | TurningWelding | - |
| 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 |
| 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 |
| Mega Machine Shop Inc Milling, Turning, Welding | Tumwater, WA | MillingTurningWelding | - |