| Laciny Brothers., Inc. Bending, Welding, Waterjet | St. Louis, MO | BendingWeldingWaterjet | - |
| Lacross Enterprises Inc Turning, Laser, Punching, Bending, Welding | Louisville, KY | TurningLaserPunchingBendingWelding | - |
| Lakecraft, Inc Turning, Bending, Welding, Grinding, Finishing | Port Clinton, OH | TurningBendingWeldingGrindingFinishing | - |
| Laser Metal Fabrication Laser, Bending, Welding, Assembly | Twin Falls, ID | LaserBendingWeldingAssembly | - |
| Laserbend, LLC Laser, Bending, Welding, Finishing | Tujunga, CA | LaserBendingWeldingFinishing | - |
| Laserform & Machine Inc Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Columbia, SC | TurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| 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 |
| Leiss Tool & Die Co Milling, Turning, Bending, Welding, Stamping, EDM, Grinding | Somerset, PA | MillingTurningBendingWeldingStampingEDMGrinding | - |
| Liberty Hill Company Milling, Turning, Swiss, Laser, Waterjet, Bending, EDM · ISO 9001, AS9100, ITAR | Huntington, WV | MillingTurningSwissLaserWaterjetBendingEDM | ISO 9001, AS9100, ITAR |
| Limestone Manufacturing LLC Milling, Turning, Laser, Bending, Welding, Metal AM, EDM, Grinding · ISO 9001, AS9100 | Somerset, KY | MillingTurningLaserBendingWeldingMetal AMEDMGrinding | ISO 9001, AS9100 |
| LJ Fabricators, Inc. Bending, Laser, Welding · ISO 9001 | Rockford, IL | BendingLaserWelding | ISO 9001 |
| Logan Machine Co Milling, Turning, Bending, Welding | Akron, OH | MillingTurningBendingWelding | - |
| Luna's Sheet Metal Inc Milling, Turning, Bending, Laser, Welding | Santa Clara, CA | MillingTurningBendingLaserWelding | - |
| Lynchburg Machining, LLC Milling, Turning, Waterjet, Bending, Welding, EDM · ISO 9001 | Lynchburg, VA | MillingTurningWaterjetBendingWeldingEDM | ISO 9001 |
| M 7 Technologies Bending, Welding · ISO 9001 | Youngstown, OH | BendingWelding | ISO 9001 |
| M B Steel Milling, Bending, Laser, Welding, Stamping | St. Louis, MO | MillingBendingLaserWeldingStamping | - |
| M&M Full Service Machine Shop Milling, Bending, Welding, Grinding, Finishing | Satellite Beach, FL | MillingBendingWeldingGrindingFinishing | - |
| M&M Metals Inc. Bending, Laser, Welding | San Antonio, TX | BendingLaserWelding | - |
| Mac Products, Inc Milling, Waterjet, Bending, Welding, Assembly · ISO 9001 | Kearny, NJ | MillingWaterjetBendingWeldingAssembly | ISO 9001 |
| Mac Smith Corp Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, Grinding | Gardena, CA | MillingTurningLaserWaterjetBendingWeldingStampingGrinding | - |
| Mac-Tech Turning, Bending, Laser, Welding | Milwaukee, WI | TurningBendingLaserWelding | - |
| Machine Time Inc Milling, Turning, Bending, Welding · ISO 9001, AS9100 | Nicholasville, KY | MillingTurningBendingWelding | ISO 9001, AS9100 |
| 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 |
| Malone Industrial Machine, L.L.C Milling, Turning, Laser, Bending, Welding | Deer Park, TX | MillingTurningLaserBendingWelding | - |
| Manor Tool & Manufacturing Co Milling, Laser, Waterjet, Bending, Welding, Stamping, EDM, Grinding, Finishing · ISO 9001, ITAR | Schiller Park, IL | MillingLaserWaterjetBendingWeldingStampingEDMGrindingFinishing | ISO 9001, ITAR |
| Maria Custom Sheet Metal Bending, Welding | Englewood, CO | BendingWelding | - |
| Marion Precision Tool, Inc Milling, Turning, Waterjet, Bending, Welding, Grinding · ISO 9001 | Ocala, FL | MillingTurningWaterjetBendingWeldingGrinding | ISO 9001 |
| Marsan Inc Bending, Welding, Assembly · ISO 9001 | Germantown, WI | BendingWeldingAssembly | ISO 9001 |
| Massie Mfg Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Finishing · ITAR | Baraga, MI | MillingTurningLaserWaterjetBendingWeldingFinishing | ITAR |
| Master Metal Products Co Bending, Welding | San Jose, CA | BendingWelding | - |
| Master Tool & Manufacturing Inc Turning, Bending, Welding, EDM, Grinding · ISO 9001, ITAR | Hiawatha, IA | TurningBendingWeldingEDMGrinding | ISO 9001, ITAR |
| MaxFab Milling, Laser, Punching, Bending, Welding, Stamping, Finishing, Assembly | Madison, AL | MillingLaserPunchingBendingWeldingStampingFinishingAssembly | - |
| Maynard Inc Bending, Welding · ISO 9001, AS9100, ITAR, NADCAP | Fayetteville, AR | BendingWelding | ISO 9001, AS9100, ITAR, NADCAP |
| McAlpin Industries Inc. Milling, Bending, Laser, Welding, Stamping | Rochester, NY | MillingBendingLaserWeldingStamping | - |
| McKenna Metal Bending, Laser, Welding, Waterjet | Portland, OR | BendingLaserWeldingWaterjet | - |
| McKiney Manufacturing Milling, Turning, Laser, Waterjet, Bending, Welding | Mitchell, NE | MillingTurningLaserWaterjetBendingWelding | - |
| Mecha Inc Milling, Bending, Welding, Waterjet · ISO 9001, ITAR, NADCAP | Raleigh, NC | MillingBendingWeldingWaterjet | ISO 9001, ITAR, NADCAP |
| Megla Manufacturing, Inc. Milling, Bending, Laser, Welding, Waterjet | National City, CA | MillingBendingLaserWeldingWaterjet | - |
| Mercury Aircraft Inc Milling, Laser, Punching, Bending, Welding, Stamping, Assembly · ISO 9001, AS9100, ITAR | Hammondsport, NY | MillingLaserPunchingBendingWeldingStampingAssembly | ISO 9001, AS9100, ITAR |
| Met International Trading Company, Inc Laser, Punching, Bending, Welding, Finishing | Houston, TX | LaserPunchingBendingWeldingFinishing | - |
| Metal Components LLC Turning, Waterjet, Bending, Welding, Finishing, Assembly · ISO 9001 | Grand Rapids, MI | TurningWaterjetBendingWeldingFinishingAssembly | ISO 9001 |
| Metal Fabricators Plus LLC Laser, Waterjet, Bending, Welding | Indianapolis, IN | LaserWaterjetBendingWelding | - |
| Metal Masterminds Laser, Waterjet, Punching, Bending, Welding, Stamping | Fountain Valley, CA | LaserWaterjetPunchingBendingWeldingStamping | - |
| Metalcraft Creative Bending, Laser, Welding | Birmingham, AL | BendingLaserWelding | - |
| Metalcraft Services Of Tampa, LLC. Bending, Welding, Waterjet, Stamping | Tampa, FL | BendingWeldingWaterjetStamping | - |
| Metalmasters Milling, Turning, Bending, Welding, Finishing | Brighton, CO | MillingTurningBendingWeldingFinishing | - |
| Metco Metal Fab. Bending, Laser, Welding | Chattanooga, TN | BendingLaserWelding | - |
| Metplas Inc Milling, Turning, Waterjet, Punching, Bending, Assembly · ISO 9001 | Natrona Heights, PA | MillingTurningWaterjetPunchingBendingAssembly | ISO 9001 |