| Farrar Aerospace LLC Milling, Turning · ISO 9001, ITAR | Ontario, CA | MillingTurning | ISO 9001, ITAR |
| Forza Engineering Group Corp Milling, Turning | Laguna Niguel, CA | MillingTurning | - |
| Franklin’s Industries Milling, Turning, Waterjet, Welding, EDM · ISO 9001, AS9100 | Poway, CA | MillingTurningWaterjetWeldingEDM | ISO 9001, AS9100 |
| Futuristics Machine, Inc. Welding · ISO 9001 | San Diego, CA | Welding | ISO 9001 |
| GC International Inc Milling, Turning, Welding, Casting, Assembly · AS9100, NADCAP | Camarillo, CA | MillingTurningWeldingCastingAssembly | AS9100, NADCAP |
| GC Machining, Inc. Milling, Turning · ISO 9001, AS9100, ITAR | Stockton, CA | MillingTurning | ISO 9001, AS9100, ITAR |
| Gear Manufacturing Inc Milling, Turning, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Anaheim, CA | MillingTurningEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| General Foundry Service Corp Casting, Finishing · ISO 9001, ITAR | San Leandro, CA | CastingFinishing | ISO 9001, ITAR |
| General Research & Manufacturing Milling, Turning · ISO 9001, AS9100, ITAR | Torrance, CA | MillingTurning | ISO 9001, AS9100, ITAR |
| Gilco Manufacturing, Inc Milling · AS9100 | Santa Fe Springs, CA | Milling | AS9100 |
| Global Aerospace Technology Corporation Milling | Valencia, CA | Milling | - |
| Global Precision Manufacturing Milling, Turning, Welding, Assembly · ISO 9001, ITAR | Grass Valley, CA | MillingTurningWeldingAssembly | ISO 9001, ITAR |
| Green's Metal Cut-Off Corp Turning, Swiss | Santa Fe Springs, CA | TurningSwiss | - |
| Group Manufacturing Services Inc Milling, Turning, Laser, Punching, Bending, Welding, Assembly · ISO 9001 | San Jose, CA | MillingTurningLaserPunchingBendingWeldingAssembly | ISO 9001 |
| Haig Precision Manufacturing Corp Milling, Turning, Laser, Punching, Bending, Welding, Stamping, EDM, Grinding, Finishing, Assembly | San Jose, CA | MillingTurningLaserPunchingBendingWeldingStampingEDMGrindingFinishingAssembly | - |
| Halfab, Inc Milling, Turning, Welding, Finishing | Livermore, CA | MillingTurningWeldingFinishing | - |
| Hallmark Metals Inc Milling, Turning, Laser, Punching, Welding, Stamping, Finishing · ISO 9001, ITAR, NADCAP | Glendora, CA | MillingTurningLaserPunchingWeldingStampingFinishing | ISO 9001, ITAR, NADCAP |
| Harcon Precision Metals, Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Finishing | San Diego, CA | MillingTurningLaserWaterjetPunchingBendingWeldingFinishing | - |
| Heighten America, Inc Milling, Turning, Welding, Assembly · ISO 9001 | Oakdale, CA | MillingTurningWeldingAssembly | ISO 9001 |
| Henry's Metal Polishing, Inc Turning, Bending, Welding, Grinding, Finishing · ISO 9001 | S El Monte, CA | TurningBendingWeldingGrindingFinishing | ISO 9001 |
| Hi Tech Precision Machining Inc Milling, Turning · ISO 9001, ISO 13485 | San Jose, CA | MillingTurning | ISO 9001, ISO 13485 |
| Hi-Tech Turning Company Turning | Anaheim, CA | Turning | - |
| Hitech Metalfab Inc Bending, Welding · ISO 9001 | Santa Clara, CA | BendingWelding | ISO 9001 |
| HM Quality Machining Inc Milling, Turning, Laser, Waterjet, Grinding | Ontario, CA | MillingTurningLaserWaterjetGrinding | - |
| HMF Corporation Bending, Laser, Welding | Anaheim, CA | BendingLaserWelding | - |
| Hogin Machine, Inc Milling, Turning, Swiss, Waterjet, Bending, Welding | Santa Ana, CA | MillingTurningSwissWaterjetBendingWelding | - |
| HP Machine & Engineering Inc Milling, Turning, EDM | San Jose, CA | MillingTurningEDM | - |
| Hubbell Machine Co Inc Milling, Turning, Finishing · ISO 9001, AS9100 | Paso Robles, CA | MillingTurningFinishing | ISO 9001, AS9100 |
| Infiniti Manufacture Milling, Welding, Finishing | Corona, CA | MillingWeldingFinishing | - |
| Infinity Precision Inc Milling, Turning, Waterjet, Bending, Grinding · ISO 9001, AS9100 | Simi Valley, CA | MillingTurningWaterjetBendingGrinding | ISO 9001, AS9100 |
| Innovation Alley Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| InSight Manufacturing Milling, Turning, Welding, Forging, Assembly | Murphys, CA | MillingTurningWeldingForgingAssembly | - |
| J & T Manufacturing & Engineering Milling, Turning | San Diego, CA | MillingTurning | - |
| J and J Custom Machining L.L.C Milling, Turning · ISO 9001 | Camarillo, CA | MillingTurning | ISO 9001 |
| 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 |
| Johnson Manufacturing Milling, Turning, Grinding · AS9100 | Huntington Beach, CA | MillingTurningGrinding | AS9100 |
| JP Metal Fabrication, Inc. Milling, Bending, Laser, Welding | Santa Clara, CA | MillingBendingLaserWelding | - |
| JWP Manufacturing Milling, Swiss, EDM | Santa Clara, CA | MillingSwissEDM | - |
| Kap Manufacturing, Inc Milling · ISO 9001 | San Dimas, CA | Milling | ISO 9001 |
| KD Precision Machining Inc Milling, Turning · AS9100 | Corona, CA | MillingTurning | AS9100 |
| Kern Steel Fabrication Inc Bending, Welding · ISO 9001 | Bakersfield, CA | BendingWelding | ISO 9001 |
| King Tek EDM & Precision Machining Milling, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, NADCAP | Anaheim, CA | MillingBendingWeldingEDM | ISO 9001, AS9100, ITAR, NADCAP |
| KNM Manufacturing Inc Bending | Fremont, CA | Bending | - |
| Krisalis Precision Machining Milling, Turning | San Andreas, CA | MillingTurning | - |
| L & R Machine Inc Milling, Turning, Grinding | Rancho Cucamonga, CA | MillingTurningGrinding | - |
| L.F. Industries, Inc Milling · ISO 9001, AS9100 | Carlsbad, CA | Milling | ISO 9001, AS9100 |
| LNT Machining Inc Milling, Turning | Santa Clara, CA | MillingTurning | - |
| Long Machine Milling, Turning, Grinding | Temecula, CA | MillingTurningGrinding | - |