| Jars Inc Milling, Waterjet, Bending, Welding, EDM, Grinding, Finishing | San Fernando, CA | MillingWaterjetBendingWeldingEDMGrindingFinishing | - |
| Jarvis Manufacturing, Inc Milling, Turning, EDM, Assembly · ISO 9001, ITAR | San Jose, CA | MillingTurningEDMAssembly | ISO 9001, ITAR |
| JD Machine Milling, Turning, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningBendingWeldingEDM | ISO 9001, AS9100, ITAR, CMMC |
| Jeglinski Group Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001 | Meadville, PA | MillingTurningWeldingEDMGrindingAssembly | ISO 9001 |
| Jenkins Machine Inc Milling, Turning, EDM, Grinding, Finishing | Bethlehem, PA | MillingTurningEDMGrindingFinishing | - |
| Jet Helseth Manufacturing Inc Turning, EDM, Finishing, Assembly · ISO 9001, ITAR | Deland, FL | TurningEDMFinishingAssembly | ISO 9001, ITAR |
| John J Steuby Co Milling, Turning, Swiss, Welding, Stamping, Casting, EDM, Finishing · ISO 9001, ITAR | Hazelwood, MO | MillingTurningSwissWeldingStampingCastingEDMFinishing | ISO 9001, ITAR |
| Jonaco Machine Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001 | Chaska, MN | MillingTurningSwissEDMGrinding | ISO 9001 |
| Jonesboro Tool & Die Co Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, EDM, Grinding · AS9100, ITAR, CMMC | Jonesboro, AR | MillingTurningLaserWaterjetBendingWeldingStampingEDMGrinding | AS9100, ITAR, CMMC |
| JWP Manufacturing Milling, Swiss, EDM | Santa Clara, CA | MillingSwissEDM | - |
| Keystone Machine & Fab, Inc Milling, Turning, EDM, Grinding | Grafton, OH | MillingTurningEDMGrinding | - |
| Ki Machine Tools & Productions Inc Milling, Turning, Bending, Welding, EDM, Grinding | Loves Park, IL | MillingTurningBendingWeldingEDMGrinding | - |
| Kilgore Manufacturing Co Inc Milling, Swiss, Bending, Welding, EDM, Finishing, Assembly · ISO 9001, ITAR | Columbia City, IN | MillingSwissBendingWeldingEDMFinishingAssembly | ISO 9001, ITAR |
| King Tek EDM & Precision Machining Milling, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, NADCAP | Anaheim, CA | MillingBendingWeldingEDM | ISO 9001, AS9100, ITAR, NADCAP |
| Korzan Enterprises Inc Milling, Turning, Waterjet, Welding, EDM, Grinding, Finishing | Orchard Park, NY | MillingTurningWaterjetWeldingEDMGrindingFinishing | - |
| Kosmo Machine Inc Milling, Turning, Welding, Casting, EDM | Sandston, VA | MillingTurningWeldingCastingEDM | - |
| Kriewall Enterprises Inc Milling, Laser, Welding, Stamping, EDM, Finishing · ISO 9001 | Romeo, MI | MillingLaserWeldingStampingEDMFinishing | ISO 9001 |
| L. C. S. Co Laser, Welding, Stamping, EDM · ISO 9001, AS9100, ITAR, NADCAP | Saint Paul, MN | LaserWeldingStampingEDM | ISO 9001, AS9100, ITAR, NADCAP |
| L&B Labs Milling, Turning, Laser, Welding, EDM, Grinding | San Jose, CA | MillingTurningLaserWeldingEDMGrinding | - |
| La Gauge Co Milling, Turning, EDM, Grinding, Finishing · ISO 9001, AS9100, ITAR | Sun Valley, CA | MillingTurningEDMGrindingFinishing | ISO 9001, AS9100, ITAR |
| LG Metalworks LLC Milling, Turning, Laser, Waterjet, Welding, EDM, Finishing | Bloomington, IN | MillingTurningLaserWaterjetWeldingEDMFinishing | - |
| LHM Engineering LLC Milling, Swiss, Laser, Waterjet, Stamping, EDM, Grinding, Finishing, Assembly · ISO 13485 | Manchester, MA | MillingSwissLaserWaterjetStampingEDMGrindingFinishingAssembly | ISO 13485 |
| 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 |
| Linear Machining Technology LLC Milling, Turning, EDM, Grinding, Finishing · ISO 9001 | Irwin, PA | MillingTurningEDMGrindingFinishing | ISO 9001 |
| M & J Manufacturing, Inc. Milling, Turning, EDM | Portland, OR | MillingTurningEDM | - |
| M-1 Tool Works, Inc Milling, Turning, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Mchenry, IL | MillingTurningEDMGrindingFinishingAssembly | ISO 9001, AS9100 |
| M-Tech Machining LLC Milling, Turning, EDM · ITAR | Edgewood, NM | MillingTurningEDM | ITAR |
| Mac Machine Company Milling, Turning, Welding, EDM, Grinding · AS9100, ITAR, NADCAP, CMMC | Baltimore, MD | MillingTurningWeldingEDMGrinding | AS9100, ITAR, NADCAP, CMMC |
| Machine Specialties, LLC Milling, Turning, Swiss, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Whitsett, NC | MillingTurningSwissWeldingEDMGrindingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| Machine Tech Inc Milling, Turning, EDM · ISO 9001 | Houma, LA | MillingTurningEDM | ISO 9001 |
| Machine Tool Engineering Milling, Turning, Swiss, Laser, Waterjet, Stamping, EDM, Grinding, Finishing · ISO 9001, AS9100, NADCAP | Charles City, IA | MillingTurningSwissLaserWaterjetStampingEDMGrindingFinishing | ISO 9001, AS9100, NADCAP |
| Machining Tech Milling, Turning, Waterjet, Welding, Stamping, EDM, Grinding | Hazle Township, PA | MillingTurningWaterjetWeldingStampingEDMGrinding | - |
| 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 |
| Manor Tool & Manufacturing Co Milling, Laser, Waterjet, Bending, Welding, Stamping, EDM, Grinding, Finishing · ISO 9001, ITAR | Schiller Park, IL | MillingLaserWaterjetBendingWeldingStampingEDMGrindingFinishing | ISO 9001, ITAR |
| 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 |
| Mars Engineering Milling, Turning, Waterjet, EDM, Grinding, Finishing, Assembly | San Leandro, CA | MillingTurningWaterjetEDMGrindingFinishingAssembly | - |
| Marvel Manufacturing Milling, Turning, Swiss, Welding, EDM, Grinding, Finishing | Lewiston, ID | MillingTurningSwissWeldingEDMGrindingFinishing | - |
| McKenzie Machining Inc Milling, Turning, EDM, Grinding · ISO 9001, AS9100, ITAR | San Jose, CA | MillingTurningEDMGrinding | ISO 9001, AS9100, ITAR |
| Menze Precision Machining, LLC Milling, Turning, Bending, Welding, EDM, Grinding, Finishing | Winter Haven, FL | MillingTurningBendingWeldingEDMGrindingFinishing | - |
| Meridian Manufacturing Inc Milling, Turning, Laser, Welding, EDM, Grinding, Finishing | Ballston Spa, NY | MillingTurningLaserWeldingEDMGrindingFinishing | - |
| MFC Netform LLC Milling, Laser, Waterjet, Bending, Welding, Stamping, Forging, EDM, Grinding · ISO 9001, IATF 16949 | Shelby Township, MI | MillingLaserWaterjetBendingWeldingStampingForgingEDMGrinding | ISO 9001, IATF 16949 |
| Micro Facture LLC Milling, Turning, EDM, Grinding, Assembly · ISO 9001, ITAR | Lancaster, PA | MillingTurningEDMGrindingAssembly | ISO 9001, ITAR |
| Micro-Matics Inc Milling, Turning, Swiss, Casting, EDM, Grinding, Assembly | Fridley, MN | MillingTurningSwissCastingEDMGrindingAssembly | - |
| Micro-Tec, Inc Milling, Turning, Welding, EDM, Finishing · ISO 9001, AS9100 | Chatsworth, CA | MillingTurningWeldingEDMFinishing | ISO 9001, AS9100 |
| Midway Machine & Instrument Company Inc Milling, Turning, EDM, Finishing · ISO 9001 | South Houston, TX | MillingTurningEDMFinishing | ISO 9001 |
| Midwest Precision LLC Milling, Turning, Casting, EDM, Grinding, Assembly · ISO 9001, ITAR | Eastlake, OH | MillingTurningCastingEDMGrindingAssembly | ISO 9001, ITAR |
| Milco Wire EDM Inc Waterjet, Stamping, EDM · AS9100, ITAR, NADCAP | Huntington Beach, CA | WaterjetStampingEDM | AS9100, ITAR, NADCAP |