| Sa Aerospace Inc Milling, Turning, Waterjet, EDM · ISO 9001, AS9100 | Sun Valley, CA | MillingTurningWaterjetEDM | ISO 9001, AS9100 |
| Sabrin Turning, Welding, EDM, Assembly · AS9100 | Pasadena, CA | TurningWeldingEDMAssembly | AS9100 |
| Salsa Prototype Specialties Milling, Turning, Waterjet · ISO 9001 | Ventura, CA | MillingTurningWaterjet | ISO 9001 |
| San Diego Precision Machining Inc Milling, Turning, Welding, EDM · ISO 9001, AS9100 | San Diego, CA | MillingTurningWeldingEDM | ISO 9001, AS9100 |
| Savage Machining Inc Milling, Turning, EDM, Finishing, Assembly · ISO 9001 | Simi Valley, CA | MillingTurningEDMFinishingAssembly | ISO 9001 |
| Schneiders Manufacturing Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001, AS9100, ITAR | Sun Valley, CA | MillingTurningSwissEDMGrinding | ISO 9001, AS9100, ITAR |
| Scotia Engineering, Inc Milling, Waterjet, Bending, Welding, Stamping, EDM, Grinding, Assembly | Santa Fe Springs, CA | MillingWaterjetBendingWeldingStampingEDMGrindingAssembly | - |
| Serrano Industries, Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001, AS9100 | Santa Fe Springs, CA | MillingTurningSwissEDMGrinding | ISO 9001, AS9100 |
| Sharp Dimension Inc Milling, Turning, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001, ITAR | Fremont, CA | MillingTurningBendingWeldingGrindingFinishingAssembly | ISO 9001, ITAR |
| Sheetmetal Engineering Inc Milling, Laser, Punching, Bending, Welding · ISO 9001, AS9100 | Simi Valley, CA | MillingLaserPunchingBendingWelding | ISO 9001, AS9100 |
| SJC Precision Inc Milling, Laser, Punching, Welding, Stamping, Grinding · ISO 9001, ITAR | Milpitas, CA | MillingLaserPunchingWeldingStampingGrinding | ISO 9001, ITAR |
| Slag Factory Milling, Laser, Welding | Oroville, CA | MillingLaserWelding | - |
| Sonoma Industries Inc Milling, Turning, Swiss · ISO 9001, AS9100, ITAR | Bell Gardens, CA | MillingTurningSwiss | ISO 9001, AS9100, ITAR |
| SP Manufacturing Inc Milling, Turning, Welding, Finishing · ISO 9001, AS9100 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100 |
| Stigtec Manufacturing Milling, Welding, EDM, Grinding, Finishing, Assembly | San Marcos, CA | MillingWeldingEDMGrindingFinishingAssembly | - |
| Stockton Tri-Industries, LLC Milling, Turning, Waterjet, Bending, Welding, Assembly | Stockton, CA | MillingTurningWaterjetBendingWeldingAssembly | - |
| Suntiger Industries LLC Welding · ISO 9001, AS9100, ITAR | Oceanside, CA | Welding | ISO 9001, AS9100, ITAR |
| Superior Pipe Fabricators Welding | Los Angeles, CA | Welding | - |
| Support Equipment Inc Milling, Turning, Welding, EDM, Finishing, Assembly · ISO 9001, AS9100, ITAR | Escondido, CA | MillingTurningWeldingEDMFinishingAssembly | ISO 9001, AS9100, ITAR |
| T & T Metals Milling, Laser, Punching, Bending, Welding, Finishing · ISO 9001 | Covina, CA | MillingLaserPunchingBendingWeldingFinishing | ISO 9001 |
| Tecma Milling, Turning, Welding, Waterjet, EDM, Stamping, Casting · ISO 9001, AS9100, ITAR, NADCAP | Sacramento, CA | MillingTurningWeldingWaterjetEDMStampingCasting | ISO 9001, AS9100, ITAR, NADCAP |
| The Champ Company Welding, Assembly | Campbell, CA | WeldingAssembly | - |
| Tiger Precision Machining Milling, Turning, Welding, Finishing | Lodi, CA | MillingTurningWeldingFinishing | - |
| TM Industries Inc Milling, Welding | Santa Clara, CA | MillingWelding | - |
| Tobar Industries Milling, Turning, Bending, Welding | San Jose, CA | MillingTurningBendingWelding | - |
| Tri Fab Associates, Inc Milling, Turning, Laser, Punching, Welding, Stamping, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Fremont, CA | MillingTurningLaserPunchingWeldingStampingGrindingFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Tri Models Inc Milling, Turning, EDM, Finishing, Assembly | Huntington Beach, CA | MillingTurningEDMFinishingAssembly | - |
| Tri Precision Sheetmetal, Inc. Bending, Laser, Welding · ISO 9001, AS9100 | Anaheim, CA | BendingLaserWelding | ISO 9001, AS9100 |
| Tridecs Corp Milling, Swiss, EDM, Grinding, Finishing, Assembly · ISO 9001 | Hayward, CA | MillingSwissEDMGrindingFinishingAssembly | ISO 9001 |
| Trinity Machining, LLC Milling, Turning, Bending, EDM, Grinding, Finishing · ISO 9001 | Grass Valley, CA | MillingTurningBendingEDMGrindingFinishing | ISO 9001 |
| Udash Corporation Milling, Laser, Waterjet, Welding, Stamping, Assembly · ISO 9001, AS9100 | Simi Valley, CA | MillingLaserWaterjetWeldingStampingAssembly | ISO 9001, 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 | - |
| Verdugo Tool & Engineering Co Inc Laser, Punching, Bending, Stamping, EDM, Grinding, Finishing · ISO 9001, ITAR | Chatsworth, CA | LaserPunchingBendingStampingEDMGrindingFinishing | ISO 9001, ITAR |
| Vicon Precision, Ltd. Liability Co Milling, Turning, Welding, Finishing, Assembly · ISO 9001 | San Jose, CA | MillingTurningWeldingFinishingAssembly | ISO 9001 |
| Vinaco Precision Machining, LLC Milling, Turning, Grinding, Finishing · ISO 9001, AS9100, NADCAP | Chatsworth, CA | MillingTurningGrindingFinishing | ISO 9001, AS9100, NADCAP |
| Vista Industries, Inc Welding, Finishing | Palmdale, CA | WeldingFinishing | - |
| 3dcam International Corp Milling, Casting, Assembly | Chatsworth, CA | MillingCastingAssembly | - |
| 5H Sheet Metal Fabrication, Inc Punching, Bending, Welding · ISO 9001, AS9100, ITAR | Orange, CA | PunchingBendingWelding | ISO 9001, AS9100, ITAR |
| 6S Machining Enterprises LLC Milling, Welding · ISO 9001, AS9100, ITAR, NADCAP | San Marcos, CA | MillingWelding | ISO 9001, AS9100, ITAR, NADCAP |
| A & D Precision Manufacturing Milling, Turning, Bending, Welding · ISO 9001, AS9100, ITAR | Anaheim, CA | MillingTurningBendingWelding | ISO 9001, AS9100, ITAR |
| A & M Engineering Inc Milling | Irwindale, CA | Milling | - |
| A Precision Machining Corp Milling · AS9100, ITAR, CMMC | Shingle Springs, CA | Milling | AS9100, ITAR, CMMC |
| Above All CNC Inc Milling, Turning · ISO 9001, AS9100, ITAR | Goleta, CA | MillingTurning | ISO 9001, AS9100, ITAR |
| Absolute Machining, Inc Milling, Turning | Chatsworth, CA | MillingTurning | - |
| AC Manufacturing Milling, Turning, Welding | San Jose, CA | MillingTurningWelding | - |
| Accuturn Corp Milling, Turning, Swiss, Grinding · AS9100 | Moreno Valley, CA | MillingTurningSwissGrinding | AS9100 |