| Pro-Tek Manufacturing Inc Bending, Welding | Livermore, CA | BendingWelding | - |
| Proto Solutions and Machining Turning, Welding, Assembly | San Diego, CA | TurningWeldingAssembly | - |
| Qualified Machine Shop Milling, Turning | San Diego, CA | MillingTurning | - |
| Qualitask Inc Milling, Turning, Swiss, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Anaheim, CA | MillingTurningSwissWeldingEDMGrindingFinishingAssembly | ISO 9001, AS9100 |
| Quality Thermal Applications Stamping, EDM, Finishing | Anaheim, CA | StampingEDMFinishing | - |
| Radical Fabrications LLC Milling, Turning, Welding, Grinding | Lancaster, CA | MillingTurningWeldingGrinding | - |
| Rah Industries Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Santa Clarita, CA | MillingTurningLaserWaterjetPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| Ram Aerospace Inc Milling, Turning, Laser, Waterjet, EDM, Grinding, Assembly · AS9100, ITAR | Brea, CA | MillingTurningLaserWaterjetEDMGrindingAssembly | AS9100, ITAR |
| Rand Machine Works Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Raw Machining Co Milling | Buena Park, CA | Milling | - |
| RBH Aerospace Inc Milling, Turning, Waterjet, Bending | Lakewood, CA | MillingTurningWaterjetBending | - |
| Richards Machining Co Inc Milling, Turning | Santa Clara, CA | MillingTurning | - |
| Rivera Solutions Inc Milling, Turning, Assembly | Gilroy, CA | MillingTurningAssembly | - |
| Robertson Machine Inc Milling, Turning | Santa Clara, CA | MillingTurning | - |
| Ronlo Engineering Ltd Turning | Camarillo, CA | Turning | - |
| Ruxco Engineering Inc Turning, EDM | Diamond Springs, CA | TurningEDM | - |
| S & B Precision Manufacturing LLC Milling | Vista, CA | Milling | - |
| S & S Commercial Fishing Equipment, Incorporated Milling, Turning, Welding | Roseville, CA | MillingTurningWelding | - |
| San Jose Die Casting & Machining Corp Casting | Lincoln, CA | Casting | - |
| Savage Machining Inc Milling, Turning, EDM, Finishing, Assembly · ISO 9001 | Simi Valley, CA | MillingTurningEDMFinishingAssembly | ISO 9001 |
| Scotia Engineering, Inc Milling, Waterjet, Bending, Welding, Stamping, EDM, Grinding, Assembly | Santa Fe Springs, CA | MillingWaterjetBendingWeldingStampingEDMGrindingAssembly | - |
| Silicon Precision Machining Inc Milling, Turning | Fremont, CA | MillingTurning | - |
| SOS Steel Co Inc Welding | Santa Clara, CA | Welding | - |
| SP Manufacturing Inc Milling, Turning, Welding, Finishing · ISO 9001, AS9100 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100 |
| Stockton Tri-Industries, LLC Milling, Turning, Waterjet, Bending, Welding, Assembly | Stockton, CA | MillingTurningWaterjetBendingWeldingAssembly | - |
| Superior Pipe Fabricators Welding | Los Angeles, CA | Welding | - |
| Systomatic Milling, Turning, EDM | Union City, CA | MillingTurningEDM | - |
| T & T Metals Milling, Laser, Punching, Bending, Welding, Finishing · ISO 9001 | Covina, CA | MillingLaserPunchingBendingWeldingFinishing | ISO 9001 |
| The Champ Company Welding, Assembly | Campbell, CA | WeldingAssembly | - |
| ThermoAir Grinding | Burbank, CA | Grinding | - |
| TJ Aerospace Inc Milling, Assembly | Garden Grove, CA | MillingAssembly | - |
| Tobar Industries Milling, Turning, Bending, Welding | San Jose, CA | MillingTurningBendingWelding | - |
| Total Concept Enterprises, Inc. Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Tough Cut Manufacturing Milling, Turning · AS9100 | Anaheim, CA | MillingTurning | AS9100 |
| Trinity Machining, LLC Milling, Turning, Bending, EDM, Grinding, Finishing · ISO 9001 | Grass Valley, CA | MillingTurningBendingEDMGrindingFinishing | ISO 9001 |
| True Position Machining Inc Milling, Turning · AS9100 | Santa Ana, CA | MillingTurning | AS9100 |
| United Sheetmetal Inc Laser, Punching, Welding, Stamping, Casting, EDM, Finishing · ISO 9001 | Fremont, CA | LaserPunchingWeldingStampingCastingEDMFinishing | ISO 9001 |
| US Precision Sheet Metal, Inc Milling, Laser, Punching, Welding, Assembly | Riverside, CA | MillingLaserPunchingWeldingAssembly | - |
| Valence Precision LLC Milling, Turning, Laser, Waterjet, Bending, Welding, Grinding | Richmond, CA | MillingTurningLaserWaterjetBendingWeldingGrinding | - |
| Valley Iron Welding | Fresno, CA | Welding | - |
| Veco Technologies, Inc. Milling, Turning, Welding, EDM | Fresno, CA | MillingTurningWeldingEDM | - |
| Vision Aerospace LLC Milling, Turning, EDM · AS9100 | Northridge, CA | MillingTurningEDM | AS9100 |
| Wildfactory Milling, Turning, Waterjet | Camarillo, CA | MillingTurningWaterjet | - |
| Wire Works EDM Inc Milling, Turning, Welding, EDM, Assembly · CMMC | Santa Ana, CA | MillingTurningWeldingEDMAssembly | CMMC |
| 6S Machining Enterprises LLC Milling, Welding · ISO 9001, AS9100, ITAR, NADCAP | San Marcos, CA | MillingWelding | ISO 9001, AS9100, ITAR, NADCAP |
| Abc Sheet Metal Laser, Waterjet, Punching, Bending, Welding · ISO 9001, AS9100 | Anaheim, CA | LaserWaterjetPunchingBendingWelding | ISO 9001, AS9100 |
| Additive Plus Metal AM · AS9100, ITAR, NADCAP, ISO 13485 | Sherman Oaks, CA | Metal AM | AS9100, ITAR, NADCAP, ISO 13485 |
| Advanced Machining Techniques Inc Milling, Turning, Welding, Assembly · ISO 9001, AS9100, ISO 13485 | Morgan Hill, CA | MillingTurningWeldingAssembly | ISO 9001, AS9100, ISO 13485 |
| Advanced Thrtical Concepts Inc Milling, Turning, Swiss, Laser, Waterjet, Welding, Grinding, Finishing | Camarillo, CA | MillingTurningSwissLaserWaterjetWeldingGrindingFinishing | - |
| Aeg Industries, Inc Milling, Turning, Bending, Grinding · ISO 9001, ITAR | Santa Rosa, CA | MillingTurningBendingGrinding | ISO 9001, ITAR |