| J.B. Anderson & Son, Inc Milling, Turning, Welding, Assembly | Irwin, PA | MillingTurningWeldingAssembly | - |
| JC Machine, Inc Milling, Turning, Swiss, Laser, Bending, Welding | Lakeland, FL | MillingTurningSwissLaserBendingWelding | - |
| JC Tool & Die, LLC Milling, Turning, Stamping, EDM, Grinding, Assembly · ISO 9001, ITAR | Hull, GA | MillingTurningStampingEDMGrindingAssembly | ISO 9001, ITAR |
| Jeb Modern Machines, Limited Turning, EDM | Republic, OH | TurningEDM | - |
| Jet Machine Works, Inc Milling, Turning | Houston, TX | MillingTurning | - |
| Jetfab LLC Milling, Turning, Laser, Waterjet, Punching, Bending, Welding | Lowell, MA | MillingTurningLaserWaterjetPunchingBendingWelding | - |
| JMS Machine, Inc Milling, Turning, EDM, Grinding | Columbia City, IN | MillingTurningEDMGrinding | - |
| Johnson Manufacturing Milling, Turning, Grinding · AS9100 | Huntington Beach, CA | MillingTurningGrinding | AS9100 |
| K&M Milling, Turning, Laser, Welding, Assembly · ISO 9001 | Cassopolis, MI | MillingTurningLaserWeldingAssembly | ISO 9001 |
| Kadon Precision Machining Turning · ISO 9001 | Rockford, IL | Turning | ISO 9001 |
| Kam Tool & Die Milling, Turning, EDM, Grinding · ISO 9001 | Zebulon, NC | MillingTurningEDMGrinding | ISO 9001 |
| Kasper Industries, Inc Milling, Turning | Gaylord, MI | MillingTurning | - |
| La Machine Shop, Inc. Milling, Turning, Bending · ISO 9001, AS9100 | Ham Lake, MN | MillingTurningBending | ISO 9001, AS9100 |
| Lathrom Manufacturing Inc Milling, Turning, Bending, Grinding · ISO 9001, ITAR | Wichita, KS | MillingTurningBendingGrinding | ISO 9001, ITAR |
| Lawson Precision Machining, Inc Milling, Turning, Welding, Grinding · ISO 9001 | Bucyrus, OH | MillingTurningWeldingGrinding | ISO 9001 |
| Lewis Precision & CNC Inc Milling, Turning, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100 | Theodore, AL | MillingTurningBendingWeldingGrindingFinishing | ISO 9001, AS9100 |
| LG Metalworks LLC Milling, Turning, Laser, Waterjet, Welding, EDM, Finishing | Bloomington, IN | MillingTurningLaserWaterjetWeldingEDMFinishing | - |
| Lindor Tool, Inc Milling, Turning, Welding, Casting, Grinding | Saint Croix Falls, WI | MillingTurningWeldingCastingGrinding | - |
| Linear Machining Technology LLC Milling, Turning, EDM, Grinding, Finishing · ISO 9001 | Irwin, PA | MillingTurningEDMGrindingFinishing | ISO 9001 |
| LV Swiss Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, AS9100, ITAR, ISO 13485 | La Verkin, UT | MillingTurningSwissGrindingFinishing | ISO 9001, AS9100, ITAR, ISO 13485 |
| M-1 Tool Works, Inc Milling, Turning, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Mchenry, IL | MillingTurningEDMGrindingFinishingAssembly | ISO 9001, AS9100 |
| Machine Time Inc Milling, Turning, Bending, Welding · ISO 9001, AS9100 | Nicholasville, KY | MillingTurningBendingWelding | ISO 9001, AS9100 |
| Machinists Inc Milling, Turning, Laser, Welding, EDM, Grinding · ISO 9001, ITAR | Seattle, WA | MillingTurningLaserWeldingEDMGrinding | ISO 9001, ITAR |
| Magnum Machining LLC Milling, Turning, Finishing | Richmond, IL | MillingTurningFinishing | - |
| Manutek Mfg LLC Milling, Turning, Waterjet · ITAR | Estacada, OR | MillingTurningWaterjet | ITAR |
| Marinette Machine LLC Turning, Welding, Grinding, Finishing | Marinette, WI | TurningWeldingGrindingFinishing | - |
| Maryland Greater Tool & Manufacturing Milling, Turning, Waterjet, Welding, Grinding, Finishing | Mountain Lake Park, MD | MillingTurningWaterjetWeldingGrindingFinishing | - |
| Master Tool & Manufacturing Inc Turning, Bending, Welding, EDM, Grinding · ISO 9001, ITAR | Hiawatha, IA | TurningBendingWeldingEDMGrinding | ISO 9001, ITAR |
| MBK Machine Corp Milling, Turning, Laser, EDM, Grinding · ITAR | Mead, CO | MillingTurningLaserEDMGrinding | ITAR |
| Mechfi Designs LLC Milling, Turning, Finishing | Westminster, CO | MillingTurningFinishing | - |
| Memac Industries Inc Milling, Turning, Welding, Grinding | Lancaster, OH | MillingTurningWeldingGrinding | - |
| Meta Manufacturing Corp Milling, Turning | Blue Ash, OH | MillingTurning | - |
| Metaltech CNC Machining LLC Milling, Turning, Bending | Portsmouth, RI | MillingTurningBending | - |
| Metzger Machine Co. Milling, Turning, Welding | Cincinnati, OH | MillingTurningWelding | - |
| Micro-Tec, Inc Milling, Turning, Welding, EDM, Finishing · ISO 9001, AS9100 | Chatsworth, CA | MillingTurningWeldingEDMFinishing | ISO 9001, AS9100 |
| Midwest Metal Fabrications Milling, Turning, Bending, Laser, Welding · ISO 9001, AS9100 | Tallmadge, OH | MillingTurningBendingLaserWelding | ISO 9001, AS9100 |
| Miller Metal Fabrication Inc Turning, Laser, Punching, Welding · ISO 9001 | Bridgeville, DE | TurningLaserPunchingWelding | ISO 9001 |
| Millrite Machine Inc Turning, Assembly · ISO 9001 | Westfield, MA | TurningAssembly | ISO 9001 |
| Mills Machine Works Inc Milling, Turning, Welding, Grinding | Lawrence, MA | MillingTurningWeldingGrinding | - |
| MMG Corp Milling, Turning, Finishing, Assembly · ISO 9001 | Ontario, CA | MillingTurningFinishingAssembly | ISO 9001 |
| Morehead Machinery Inc Milling, Turning, Welding, EDM, Grinding | Elkhart, IN | MillingTurningWeldingEDMGrinding | - |
| Moultrie Tool & Manufacturing Co Inc Milling, Turning, Bending, Welding, EDM, Stamping · ISO 9001 | Memphis, TN | MillingTurningBendingWeldingEDMStamping | ISO 9001 |
| Mpi Manufacturing Co. LLC Milling, Turning | Grovetown, GA | MillingTurning | - |
| N & S Flame Spray, LLC Milling, Turning, Welding, Grinding | Mannford, OK | MillingTurningWeldingGrinding | - |
| Next Level Manufacturing LLC Milling, Turning, Waterjet, EDM | Jenison, MI | MillingTurningWaterjetEDM | - |
| Niagara Manufacturing Co Milling, Turning, Bending, Welding | Erie, PA | MillingTurningBendingWelding | - |
| Nolte Precise Manufacturing Inc Milling, Turning, Swiss · ISO 9001, AS9100 | Cincinnati, OH | MillingTurningSwiss | ISO 9001, AS9100 |
| North Country Engineering Inc Milling, Turning, Laser, Grinding · ISO 9001, AS9100, ITAR | Derby, VT | MillingTurningLaserGrinding | ISO 9001, AS9100, ITAR |
| North East Precision CNC Milling, Turning · ISO 9001, ITAR | Dover, NH | MillingTurning | ISO 9001, ITAR |
| Northern Lucus Machine Shop Turning, Punching, Welding | Lubbock, TX | TurningPunchingWelding | - |