| 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 |
| 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 |
| Miramar Metal Processing Inc Welding, Finishing · ITAR, NADCAP | San Diego, CA | WeldingFinishing | ITAR, NADCAP |
| Modern Custom Fabrication Welding | Fresno, CA | Welding | - |
| Modus Advanced Milling, Waterjet, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Carlsbad, CA | MillingWaterjetFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Mono Engineering Corp Turning, Welding, EDM · ISO 9001 | Chatsworth, CA | TurningWeldingEDM | ISO 9001 |
| Moseys Production Machinists, Inc Milling, Turning · ISO 9001, AS9100, ITAR, NADCAP | Anaheim, CA | MillingTurning | ISO 9001, AS9100, ITAR, NADCAP |
| MVC Wire Milling, Turning, EDM, Grinding · ISO 9001 | Mission Viejo, CA | MillingTurningEDMGrinding | ISO 9001 |
| MVN Machining LLC Milling, Turning | Santa Clara, CA | MillingTurning | - |
| Nace Sheet Metal Co Bending, Laser, Welding | Anaheim, CA | BendingLaserWelding | - |
| New World Machining Inc Milling, Turning, Welding | San Jose, CA | MillingTurningWelding | - |
| Next Intent, Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, ITAR | San Luis Obispo, CA | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, ITAR |
| Nexus Automation Milling, Welding, EDM, Assembly · ISO 9001, ITAR, ISO 13485 | Livermore, CA | MillingWeldingEDMAssembly | ISO 9001, ITAR, ISO 13485 |
| Nominal Machining LLC Milling, Turning, Welding · ISO 9001, AS9100, ITAR | Elk Grove, CA | MillingTurningWelding | ISO 9001, AS9100, ITAR |
| O & Y Precision Inc Milling, Laser, Waterjet, Bending, Welding, EDM, Finishing, Assembly | Morgan Hill, CA | MillingLaserWaterjetBendingWeldingEDMFinishingAssembly | - |
| 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 |
| Omikron Engineering, Inc Milling, Turning, Swiss, Assembly · ISO 9001 | Chatsworth, CA | MillingTurningSwissAssembly | 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 Precision Machine Inc Milling, Turning, Welding | Sonora, CA | MillingTurningWelding | - |
| 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 |
| Pen Manufacturing Milling, Turning, Bending, Welding · ISO 9001, AS9100, ITAR, NADCAP | Anaheim, CA | MillingTurningBendingWelding | ISO 9001, AS9100, ITAR, NADCAP |
| 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 |
| PHD Machining LLC Milling, EDM, Assembly | Santa Clara, CA | MillingEDMAssembly | - |
| PHES Machining Milling, Turning | Riverside, CA | MillingTurning | - |
| Pimtad Aerospace LLC Milling, Turning, Swiss, Welding, Grinding, Assembly · AS9100 | Valencia, CA | MillingTurningSwissWeldingGrindingAssembly | AS9100 |
| 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 |
| Precision Machining & Fab Milling, Turning, Bending, Laser, Welding, Waterjet · ISO 9001, AS9100, ITAR | Anaheim, CA | MillingTurningBendingLaserWeldingWaterjet | ISO 9001, AS9100, ITAR |
| Precision Manufacturing Milling, Turning · ISO 9001, ITAR, ISO 13485 | Roseville, CA | MillingTurning | ISO 9001, ITAR, ISO 13485 |
| Prisecter Aerospace and Defense LLC Milling, Turning, Waterjet, Welding, Assembly · AS9100, ITAR, CMMC | Auburn, CA | MillingTurningWaterjetWeldingAssembly | AS9100, ITAR, CMMC |
| Prism Aerospace Bending, Assembly · AS9100, CMMC | Riverside, CA | BendingAssembly | AS9100, CMMC |
| Proformance Manufacturing Inc Turning, Stamping · ISO 9001 | Corona, CA | TurningStamping | ISO 9001 |
| Proto Solutions and Machining Turning, Welding, Assembly | San Diego, CA | TurningWeldingAssembly | - |
| PTG Precision LLC Milling, Turning, Swiss, Welding, Grinding, Assembly · ISO 9001, AS9100, ITAR, CMMC | Gardena, CA | MillingTurningSwissWeldingGrindingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Q3-Cnc, Inc Milling, Turning | San Diego, CA | MillingTurning | - |
| Quality Machining & Design Inc Milling, EDM · ISO 9001 | San Jose, CA | MillingEDM | ISO 9001 |
| Quality Thermal Applications Stamping, EDM, Finishing | Anaheim, CA | StampingEDMFinishing | - |
| R & G Precision Machining Inc Milling, Turning · ISO 9001, AS9100 | Oceanside, CA | MillingTurning | ISO 9001, AS9100 |
| R.M. Baker Machine & Tool, Inc Milling, Welding, EDM, Grinding, Finishing | Covina, CA | MillingWeldingEDMGrindingFinishing | - |