| California Sheet Metal Bending, Laser, Welding, Waterjet | El Cajon, CA | BendingLaserWeldingWaterjet | - |
| CalWest MFG Milling, Turning, Laser, Waterjet, Bending, Welding · ISO 9001, ITAR | Fontana, CA | MillingTurningLaserWaterjetBendingWelding | ISO 9001, ITAR |
| CapXFab Welding | Reno, NV | Welding | - |
| Carlisle Machine Works Inc Milling, Turning, Bending, Welding, EDM, Grinding | Millville, NJ | MillingTurningBendingWeldingEDMGrinding | - |
| Carollo Metal Works Welding | Chalmette, LA | Welding | - |
| Carver Machine Works Inc Waterjet, Welding, Assembly · ISO 9001, AS9100, NADCAP | Washington, NC | WaterjetWeldingAssembly | ISO 9001, AS9100, NADCAP |
| CBM Fabrication Inc Milling, Turning, Waterjet, Welding, EDM, Grinding, Finishing | Ballston Lake, NY | MillingTurningWaterjetWeldingEDMGrindingFinishing | - |
| Center Tool Co Milling, Turning, Welding, Stamping, EDM, Grinding · ISO 9001 | Hampshire, IL | MillingTurningWeldingStampingEDMGrinding | ISO 9001 |
| Centerline Engineered Solutions, Inc Milling, Turning, Laser, Bending, Welding · ISO 9001 | Greenwood, SC | MillingTurningLaserBendingWelding | ISO 9001 |
| Centerline Machine, LLC Milling, Turning, Waterjet, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Waupaca, WI | MillingTurningWaterjetBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Central Precision Inc Milling, Laser, Punching, Bending, Welding, Grinding, Finishing · ISO 9001 | Boonsboro, MD | MillingLaserPunchingBendingWeldingGrindingFinishing | ISO 9001 |
| Central Valley Machine Inc Milling, Turning, Waterjet, Bending, Welding, EDM · AS9100, ITAR | Logan, UT | MillingTurningWaterjetBendingWeldingEDM | AS9100, ITAR |
| Certified Metal Finishing Welding, Casting, Finishing · ISO 9001, AS9100, NADCAP | Pompano Beach, FL | WeldingCastingFinishing | ISO 9001, AS9100, NADCAP |
| CF Metals Welding | Fort Worth, TX | Welding | - |
| Chesapeake Machine Co Milling, Welding | Baltimore, MD | MillingWelding | - |
| Chicago CNC Machining Co. Milling, Turning, Bending, Welding | Hodgkins, IL | MillingTurningBendingWelding | - |
| Chicago Magnesium Casting Co Welding, Casting · AS9100, NADCAP | Blue Island, IL | WeldingCasting | AS9100, NADCAP |
| Churchmen's Machine Company Milling, Turning, Laser, Waterjet, Welding, Grinding, Finishing | North East, MD | MillingTurningLaserWaterjetWeldingGrindingFinishing | - |
| CJ Precision Machine Inc Milling, Turning, Welding, Finishing · ISO 9001 | Boise, ID | MillingTurningWeldingFinishing | ISO 9001 |
| Clark Fixture Technologies Inc Bending, Welding · ISO 9001, AS9100 | Bowling Green, OH | BendingWelding | ISO 9001, AS9100 |
| Clark Machine Corporation Welding, Finishing | Baltimore, MD | WeldingFinishing | - |
| Class A Tooling Inc Milling, Turning, Bending, Welding, Stamping, EDM, Grinding | Cabot, AR | MillingTurningBendingWeldingStampingEDMGrinding | - |
| Classic Machine & Engineering Milling, Turning, Laser, Welding, Grinding | Ashland, VA | MillingTurningLaserWeldingGrinding | - |
| CM Fabricating Bending, Welding | Kansas City, MO | BendingWelding | - |
| CNC Syndicate Welding | Ravenswood, WV | Welding | - |
| Coanda Company LLC, the Milling, Turning, Waterjet, Welding · ISO 9001, AS9100 | Shawnee, OK | MillingTurningWaterjetWelding | ISO 9001, AS9100 |
| Coast Aerospace Manufacturing, Inc Milling, Welding · AS9100, ITAR | Placentia, CA | MillingWelding | AS9100, ITAR |
| Collins Machine Works Welding, Grinding · CMMC | Portsmouth, VA | WeldingGrinding | CMMC |
| Colonial Welding, LLC Turning, Laser, Bending, Welding, Finishing | Norfolk, VA | TurningLaserBendingWeldingFinishing | - |
| Columbia Machine Works, Inc Milling, Turning, Welding, Stamping, Casting · ISO 9001, ITAR | Columbia, TN | MillingTurningWeldingStampingCasting | ISO 9001, ITAR |
| Columbus Machine Works Milling, Turning, Bending, Welding, EDM, Casting | Columbus, OH | MillingTurningBendingWeldingEDMCasting | - |
| Comet Fabricating & Welding Co Laser, Bending, Welding | Rockford, IL | LaserBendingWelding | - |
| Commercial Metal Fabricators, Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding | Dayton, OH | MillingTurningLaserWaterjetPunchingBendingWelding | - |
| Commercial Tool & Die Inc Milling, Turning, Welding, Grinding | Marshall, VA | MillingTurningWeldingGrinding | - |
| Complex Fabricators, Inc. Bending, Laser, Welding, Stamping · AS9100 | Salt Lake City, UT | BendingLaserWeldingStamping | AS9100 |
| Compucraft Industries, Inc Waterjet, Punching, Bending, Welding, EDM, Finishing, Assembly · AS9100, NADCAP | Santee, CA | WaterjetPunchingBendingWeldingEDMFinishingAssembly | AS9100, NADCAP |
| Computer Components Corporation Milling, Turning, Punching, Bending, Welding, Assembly · ISO 9001, ITAR | Philadelphia, PA | MillingTurningPunchingBendingWeldingAssembly | ISO 9001, ITAR |
| Concise Manufacturing Inc Milling, Turning, Welding, EDM | Salisbury, NC | MillingTurningWeldingEDM | - |
| Connelly Machine WKS Milling, Turning, Waterjet, Welding, Grinding · ISO 9001, ITAR | Santa Ana, CA | MillingTurningWaterjetWeldingGrinding | ISO 9001, ITAR |
| Conroe Machine, LLC Milling, Turning, Laser, Bending, Welding, EDM, Grinding, Finishing · ISO 9001 | Conroe, TX | MillingTurningLaserBendingWeldingEDMGrindingFinishing | ISO 9001 |
| Consolidated Metal Products Milling, Turning, Bending, Laser, Welding, Stamping · ISO 9001 | Grand Rapids, MI | MillingTurningBendingLaserWeldingStamping | ISO 9001 |
| Container Products Company, LLC Welding | Currie, NC | Welding | - |
| Conti Tool & Die, Inc Milling, Turning, Bending, Welding, Grinding | Akron, OH | MillingTurningBendingWeldingGrinding | - |
| Continental Industries Bending, Laser, Welding | Anaheim, CA | BendingLaserWelding | - |
| Continental Machining Co Milling, Turning, Welding, EDM | Albuquerque, NM | MillingTurningWeldingEDM | - |
| Copen Machine, Inc Milling, Turning, Swiss, Welding, Grinding · ISO 9001 | Kent, OH | MillingTurningSwissWeldingGrinding | ISO 9001 |
| Core-X LLC Laser, Welding | Commerce City, CO | LaserWelding | - |
| Cornell Forge Company Welding, Forging, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Chicago, IL | WeldingForgingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| Coronado Steel Co Turning, Welding, Casting, Metal AM | Youngstown, OH | TurningWeldingCastingMetal AM | - |
| Covert Manufacturing, Inc Milling, Turning, Welding, Grinding · ISO 9001, ITAR, IATF 16949 | Galion, OH | MillingTurningWeldingGrinding | ISO 9001, ITAR, IATF 16949 |