| J Mark Co Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Vista, CA | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Jaco Engineering Milling, Turning, Bending, Welding, EDM, Grinding, Finishing, Assembly · NADCAP | Anaheim, CA | MillingTurningBendingWeldingEDMGrindingFinishingAssembly | NADCAP |
| Jarvis Manufacturing, Inc Milling, Turning, EDM, Assembly · ISO 9001, ITAR | San Jose, CA | MillingTurningEDMAssembly | ISO 9001, ITAR |
| JMT Inc Milling, Turning · ISO 9001, AS9100, ITAR, CMMC | Norwalk, CA | MillingTurning | ISO 9001, AS9100, ITAR, CMMC |
| Joels Machine Shop Inc Milling, Turning, Grinding | El Monte, CA | MillingTurningGrinding | - |
| Johnson Manufacturing Milling, Turning, Grinding · AS9100 | Huntington Beach, CA | MillingTurningGrinding | AS9100 |
| Krisalis Precision Machining Milling, Turning | San Andreas, CA | MillingTurning | - |
| L.F. Industries, Inc Milling · ISO 9001, AS9100 | Carlsbad, CA | Milling | ISO 9001, AS9100 |
| L&B Labs Milling, Turning, Laser, Welding, EDM, Grinding | San Jose, CA | MillingTurningLaserWeldingEDMGrinding | - |
| La Gauge Co Milling, Turning, EDM, Grinding, Finishing · ISO 9001, AS9100, ITAR | Sun Valley, CA | MillingTurningEDMGrindingFinishing | ISO 9001, AS9100, ITAR |
| Langill's General Machine Inc Milling, Welding | Sacramento, CA | MillingWelding | - |
| Lean Manufacturing Group LLC Milling, Turning, EDM · AS9100, ITAR | Valencia, CA | MillingTurningEDM | AS9100, ITAR |
| Long Machine Milling, Turning, Grinding | Temecula, CA | MillingTurningGrinding | - |
| Loutech LLC Milling, Turning, Swiss, Finishing · ISO 9001, AS9100, ITAR | Chino, CA | MillingTurningSwissFinishing | ISO 9001, AS9100, ITAR |
| LT CNC Machining Inc. Milling, Turning, Welding · AS9100 | San Diego, CA | MillingTurningWelding | AS9100 |
| Ltmt Machining LLC Milling, Finishing | Santa Clara, CA | MillingFinishing | - |
| M & L Precision Machining, Inc EDM | Morgan Hill, CA | EDM | - |
| M & R Engineering Milling, Turning, Swiss, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP | Orange, CA | MillingTurningSwissFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP |
| Machina Labs Inc Stamping · ITAR, CMMC | Chatsworth, CA | Stamping | ITAR, CMMC |
| Machine Dimension, Inc Milling | San Jose, CA | Milling | - |
| Machinist Lab Milling, EDM | San Diego, CA | MillingEDM | - |
| Manufacturing Standard, LLC Milling, Turning, Swiss, Stamping, Casting · ISO 9001, AS9100, IATF 16949 | Poway, CA | MillingTurningSwissStampingCasting | ISO 9001, AS9100, IATF 16949 |
| Marton Precision MF Milling, Turning, Waterjet, Welding, EDM, Finishing · ISO 9001, AS9100, ITAR | Fullerton, CA | MillingTurningWaterjetWeldingEDMFinishing | ISO 9001, AS9100, ITAR |
| 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 | - |
| Metalid Manufacturing Inc Milling · ISO 9001 | Pacoima, CA | Milling | ISO 9001 |
| Metri Tech Engineering Inc Milling, EDM, Assembly · ISO 9001, AS9100 | Huntington Beach, CA | MillingEDMAssembly | ISO 9001, AS9100 |
| Millipart, Inc Milling, Turning · ISO 9001, AS9100 | Glendora, CA | MillingTurning | ISO 9001, AS9100 |
| Milner's Anodizing Finishing · NADCAP | Santa Rosa, CA | Finishing | NADCAP |
| MKM Manufacturing & Design, Inc Finishing | Newbury Park, CA | Finishing | - |
| Moseys Production Machinists, Inc Milling, Turning · ISO 9001, AS9100, ITAR, NADCAP | Anaheim, CA | MillingTurning | ISO 9001, AS9100, ITAR, NADCAP |
| My Machine Inc Milling · ISO 9001, AS9100, CMMC | Baldwin Park, CA | Milling | ISO 9001, AS9100, CMMC |
| Nace Sheet Metal Co Bending, Laser, Welding | Anaheim, CA | BendingLaserWelding | - |
| 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 |
| Norotos, Inc Turning, Forging | Santa Ana, CA | TurningForging | - |
| Odyssey Machining Milling, Finishing · ISO 9001, ITAR | San Jose, CA | MillingFinishing | ISO 9001, ITAR |
| Omikron Engineering, Inc Milling, Turning, Swiss, Assembly · ISO 9001 | Chatsworth, CA | MillingTurningSwissAssembly | ISO 9001 |
| 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 | - |
| Pacon Mfg, Inc Milling, Turning, Welding, Finishing · ISO 9001 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001 |
| 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 |
| PHD Machining LLC Milling, EDM, Assembly | Santa Clara, CA | MillingEDMAssembly | - |
| PL Machine Corporation Milling, Turning, Bending, Finishing · ISO 9001 | Los Alamitos, CA | MillingTurningBendingFinishing | ISO 9001 |
| Plasidyne Engineering & Manufacturing Milling, Turning · ISO 9001, AS9100, ITAR | Long Beach, CA | MillingTurning | ISO 9001, AS9100, ITAR |