| 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 | - |
| Martin's Metal Fabrication & Welding, Inc Milling, Turning, Laser, Waterjet, Bending, Welding | Vacaville, CA | MillingTurningLaserWaterjetBendingWelding | - |
| McKenzie Machining Inc Milling, Turning, EDM, Grinding · ISO 9001, AS9100, ITAR | San Jose, CA | MillingTurningEDMGrinding | ISO 9001, AS9100, ITAR |
| Megla Manufacturing, Inc. Milling, Bending, Laser, Welding, Waterjet | National City, CA | MillingBendingLaserWeldingWaterjet | - |
| Melton Sheet Metal Bending, Welding | Fresno, CA | BendingWelding | - |
| Metal Fusion Inc Milling, Turning, Welding, Grinding | Redwood City, CA | MillingTurningWeldingGrinding | - |
| Metal Masterminds Laser, Waterjet, Punching, Bending, Welding, Stamping | Fountain Valley, CA | LaserWaterjetPunchingBendingWeldingStamping | - |
| Metalid Manufacturing Inc Milling · ISO 9001 | Pacoima, CA | Milling | ISO 9001 |
| Micro-Tec, Inc Milling, Turning, Welding, EDM, Finishing · ISO 9001, AS9100 | Chatsworth, CA | MillingTurningWeldingEDMFinishing | ISO 9001, AS9100 |
| Microform Precision LLC Turning, Bending, Laser, Welding, Waterjet | Sacramento, CA | TurningBendingLaserWeldingWaterjet | - |
| Mikelson Machine Shop, Inc Milling, Turning | S El Monte, CA | MillingTurning | - |
| Milco Wire EDM Inc Waterjet, Stamping, EDM · AS9100, ITAR, NADCAP | Huntington Beach, CA | WaterjetStampingEDM | AS9100, ITAR, NADCAP |
| Miller CNC Milling, Turning, Welding, Grinding · ISO 9001, AS9100 | Chula Vista, CA | MillingTurningWeldingGrinding | ISO 9001, AS9100 |
| Miramar Metal Processing Inc Welding, Finishing · ITAR, NADCAP | San Diego, CA | WeldingFinishing | ITAR, NADCAP |
| MMG Corp Milling, Turning, Finishing, Assembly · ISO 9001 | Ontario, CA | MillingTurningFinishingAssembly | ISO 9001 |
| Mono Engineering Corp Turning, Welding, EDM · ISO 9001 | Chatsworth, CA | TurningWeldingEDM | ISO 9001 |
| Nace Sheet Metal Co Bending, Laser, Welding | Anaheim, CA | BendingLaserWelding | - |
| National Metal Stampings - Temecula Valley Milling, Turning, Welding, Stamping, EDM, Grinding · ISO 9001 | Lancaster, CA | MillingTurningWeldingStampingEDMGrinding | ISO 9001 |
| Next Intent, Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, ITAR | San Luis Obispo, CA | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, ITAR |
| Next Tech Manufacturing Inc Milling, Welding, Finishing | Santa Clara, CA | MillingWeldingFinishing | - |
| Nominal Machining LLC Milling, Turning, Welding · ISO 9001, AS9100, ITAR | Elk Grove, CA | MillingTurningWelding | ISO 9001, AS9100, ITAR |
| Noron Precision Machining Inc Milling, Turning, Grinding, Finishing, Assembly · ISO 9001, ITAR | Sunnyvale, CA | MillingTurningGrindingFinishingAssembly | ISO 9001, ITAR |
| Odyssey Machining Milling, Finishing · ISO 9001, ITAR | San Jose, CA | MillingFinishing | ISO 9001, ITAR |
| Omanson Precision Engineering, Inc Milling, Finishing · ISO 9001, AS9100 | Chino, CA | MillingFinishing | ISO 9001, AS9100 |
| Omega Precision Milling, Turning · ISO 9001 | Santa Fe Springs, CA | MillingTurning | ISO 9001 |
| Omw Corp Milling, Assembly · ISO 9001, AS9100, CMMC | Novato, CA | MillingAssembly | ISO 9001, AS9100, CMMC |
| Opti-Forms Inc Stamping, EDM, Finishing · ISO 9001, ITAR | Temecula, CA | StampingEDMFinishing | ISO 9001, ITAR |
| Optima Precision Milling, Turning, Bending, Welding, EDM, Metal AM · ISO 9001, AS9100, ISO 13485, NADCAP | San Jose, CA | MillingTurningBendingWeldingEDMMetal AM | ISO 9001, AS9100, ISO 13485, NADCAP |
| Orange County Sheet Metal Shop Bending, Laser, Welding, Stamping | Anaheim, CA | BendingLaserWeldingStamping | - |
| Pacific Maritime Industries Corp Milling, Turning, Laser, Waterjet, Punching, Bending, Welding · ISO 9001 | San Diego, CA | MillingTurningLaserWaterjetPunchingBendingWelding | ISO 9001 |
| 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 |
| PCL, LLC Milling, Turning, Swiss, Finishing · NADCAP | Oxnard, CA | MillingTurningSwissFinishing | NADCAP |
| Peacock Tool & Engineering Milling, Turning · AS9100, ITAR, CMMC | Spring Valley, CA | MillingTurning | AS9100, ITAR, CMMC |
| Pegasus Machining Solutions Milling, Turning, Finishing | San Jose, CA | MillingTurningFinishing | - |
| Perforated Panels Laser, Waterjet, Bending, Welding | Pacoima, CA | LaserWaterjetBendingWelding | - |
| Pervan Industries Milling, Turning, Waterjet, Punching, Bending · ISO 9001, AS9100 | Compton, CA | MillingTurningWaterjetPunchingBending | ISO 9001, AS9100 |
| Petersen Precision Engineering LLC Milling, Turning, Swiss, EDM, Grinding, Finishing · ISO 9001, AS9100, ISO 13485 | Redwood City, CA | MillingTurningSwissEDMGrindingFinishing | ISO 9001, AS9100, ISO 13485 |
| Pimtad Aerospace LLC Milling, Turning, Swiss, Welding, Grinding, Assembly · AS9100 | Valencia, CA | MillingTurningSwissWeldingGrindingAssembly | AS9100 |
| Plasidyne Engineering & Manufacturing Milling, Turning · ISO 9001, AS9100, ITAR | Long Beach, CA | MillingTurning | ISO 9001, AS9100, ITAR |
| PNM Co Milling, Turning · ISO 9001 | Fresno, CA | MillingTurning | ISO 9001 |
| Powers Bros Machine Inc Welding, Grinding | Montebello, CA | WeldingGrinding | - |
| Precision Components Mfg Co Milling, Turning | Pasadena, CA | MillingTurning | - |
| Precision Ferrites & Ceramic Milling, Grinding · AS9100 | Huntington Beach, CA | MillingGrinding | AS9100 |
| Prisecter Aerospace and Defense LLC Milling, Turning, Waterjet, Welding, Assembly · AS9100, ITAR, CMMC | Auburn, CA | MillingTurningWaterjetWeldingAssembly | AS9100, ITAR, CMMC |
| Process Stainless Lab Welding, Finishing, Assembly · ISO 9001 | Milpitas, CA | WeldingFinishingAssembly | ISO 9001 |
| Proformance Manufacturing Inc Turning, Stamping · ISO 9001 | Corona, CA | TurningStamping | ISO 9001 |
| Proto Solutions and Machining Turning, Welding, Assembly | San Diego, CA | TurningWeldingAssembly | - |
| Q3-Cnc, Inc Milling, Turning | San Diego, CA | MillingTurning | - |