| J Mark Co Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Vista, CA | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Jarvis Manufacturing, Inc Milling, Turning, EDM, Assembly · ISO 9001, ITAR | San Jose, CA | MillingTurningEDMAssembly | ISO 9001, ITAR |
| Johnson Manufacturing Milling, Turning, Grinding · AS9100 | Huntington Beach, CA | MillingTurningGrinding | AS9100 |
| Kap Manufacturing, Inc Milling · ISO 9001 | San Dimas, CA | Milling | ISO 9001 |
| Kaydek Machining, Inc Milling, Turning, Finishing · ISO 9001, AS9100 | San Jose, CA | MillingTurningFinishing | ISO 9001, AS9100 |
| KB Sheetmetal Fabrication, Inc Turning, Bending, Welding, Finishing · ISO 9001 | Fountain Valley, CA | TurningBendingWeldingFinishing | ISO 9001 |
| Kern Steel Fabrication Inc Bending, Welding · ISO 9001 | Bakersfield, CA | BendingWelding | ISO 9001 |
| L&B Labs Milling, Turning, Laser, Welding, EDM, Grinding | San Jose, CA | MillingTurningLaserWeldingEDMGrinding | - |
| Langill's General Machine Inc Milling, Welding | Sacramento, CA | MillingWelding | - |
| Laserbend, LLC Laser, Bending, Welding, Finishing | Tujunga, CA | LaserBendingWeldingFinishing | - |
| Lean Manufacturing Group LLC Milling, Turning, EDM · AS9100, ITAR | Valencia, CA | MillingTurningEDM | AS9100, ITAR |
| Lightsout CNC Manufacturing Company Milling · ISO 9001, ITAR, NADCAP, ISO 13485, CMMC | Beverly Hills, CA | Milling | ISO 9001, ITAR, NADCAP, ISO 13485, CMMC |
| LNP Machining Milling, Turning, Welding, Finishing · ISO 9001, AS9100, ITAR, ISO 13485 | San Jose, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100, ITAR, ISO 13485 |
| LNT Machining Inc Milling, Turning | Santa Clara, CA | MillingTurning | - |
| Long Machine Milling, Turning, Grinding | Temecula, CA | MillingTurningGrinding | - |
| LP Precision, Inc Milling, Turning, Grinding, Finishing | Santa Clara, CA | MillingTurningGrindingFinishing | - |
| Luna's Sheet Metal Inc Milling, Turning, Bending, Laser, Welding | Santa Clara, CA | MillingTurningBendingLaserWelding | - |
| M & L Precision Machining, Inc EDM | Morgan Hill, CA | EDM | - |
| M'kaddesh Group LLC Milling, Turning · AS9100 | Cerritos, CA | MillingTurning | AS9100 |
| Mac Cal Co Welding · ISO 13485 | San Jose, CA | Welding | ISO 13485 |
| Mac Smith Corp Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, Grinding | Gardena, CA | MillingTurningLaserWaterjetBendingWeldingStampingGrinding | - |
| Magna Tool Inc Milling, Turning, Welding · AS9100 | Cypress, CA | MillingTurningWelding | AS9100 |
| Manufacturing Standard, LLC Milling, Turning, Swiss, Stamping, Casting · ISO 9001, AS9100, IATF 16949 | Poway, CA | MillingTurningSwissStampingCasting | ISO 9001, AS9100, IATF 16949 |
| Mars Engineering Milling, Turning, Waterjet, EDM, Grinding, Finishing, Assembly | San Leandro, CA | MillingTurningWaterjetEDMGrindingFinishingAssembly | - |
| Marton Precision MF Milling, Turning, Waterjet, Welding, EDM, Finishing · ISO 9001, AS9100, ITAR | Fullerton, CA | MillingTurningWaterjetWeldingEDMFinishing | ISO 9001, AS9100, ITAR |
| Mass Precision Inc Welding, Assembly · ISO 9001, ISO 13485 | San Jose, CA | WeldingAssembly | ISO 9001, ISO 13485 |
| Master Precision Machining Milling, Welding · ISO 9001, AS9100 | Santa Clara, CA | MillingWelding | ISO 9001, AS9100 |
| Maxpol Precision Machining Milling, Turning | Morgan Hill, CA | MillingTurning | - |
| McKenzie Machining Inc Milling, Turning, EDM, Grinding · ISO 9001, AS9100, ITAR | San Jose, CA | MillingTurningEDMGrinding | ISO 9001, AS9100, ITAR |
| Melton Sheet Metal Bending, Welding | Fresno, CA | BendingWelding | - |
| Metal Fusion Inc Milling, Turning, Welding, Grinding | Redwood City, CA | MillingTurningWeldingGrinding | - |
| Metal Master Inc Milling, Welding | San Diego, CA | MillingWelding | - |
| Metal Masterminds Laser, Waterjet, Punching, Bending, Welding, Stamping | Fountain Valley, CA | LaserWaterjetPunchingBendingWeldingStamping | - |
| Millennium Metalcraft, Inc Milling, Laser, Bending, Welding, Finishing, Assembly · ISO 9001 | Fremont, CA | MillingLaserBendingWeldingFinishingAssembly | ISO 9001 |
| Millipart, Inc Milling, Turning · ISO 9001, AS9100 | Glendora, CA | MillingTurning | ISO 9001, AS9100 |
| Millworx Precision Machining Inc Milling, Turning · ISO 9001, AS9100 | Corona, CA | MillingTurning | ISO 9001, AS9100 |
| Milner's Anodizing Finishing · NADCAP | Santa Rosa, CA | Finishing | NADCAP |
| Milo Engineering Milling, Turning, Grinding, Finishing · ISO 9001 | Torrance, CA | MillingTurningGrindingFinishing | ISO 9001 |
| Morena Welding Inc Welding | San Diego, CA | Welding | - |
| MVN Machining LLC Milling, Turning | Santa Clara, CA | MillingTurning | - |
| National Metal Stampings - Temecula Valley Milling, Turning, Welding, Stamping, EDM, Grinding · ISO 9001 | Lancaster, CA | MillingTurningWeldingStampingEDMGrinding | ISO 9001 |
| New World Machining Inc Milling, Turning, Welding | San Jose, CA | MillingTurningWelding | - |
| Next Tech Manufacturing Inc Milling, Welding, Finishing | Santa Clara, CA | MillingWeldingFinishing | - |
| Norotos, Inc Turning, Forging | Santa Ana, CA | TurningForging | - |
| Odyssey Machining Milling, Finishing · ISO 9001, ITAR | San Jose, CA | MillingFinishing | ISO 9001, ITAR |
| Pacon Mfg, Inc Milling, Turning, Welding, Finishing · ISO 9001 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001 |
| Parallax Manufacturing LLC Milling, Turning, Bending, Welding, Stamping, Assembly · NADCAP | Lake Elsinore, CA | MillingTurningBendingWeldingStampingAssembly | NADCAP |
| Pegasus Machining Solutions Milling, Turning, Finishing | San Jose, CA | MillingTurningFinishing | - |
| Petersen Precision Engineering LLC Milling, Turning, Swiss, EDM, Grinding, Finishing · ISO 9001, AS9100, ISO 13485 | Redwood City, CA | MillingTurningSwissEDMGrindingFinishing | ISO 9001, AS9100, ISO 13485 |
| PL Machine Corporation Milling, Turning, Bending, Finishing · ISO 9001 | Los Alamitos, CA | MillingTurningBendingFinishing | ISO 9001 |