| Cnspeed Machining LLC Milling, Turning · ITAR | Salisbury, NC | MillingTurning | ITAR |
| Coanda Company LLC, the Milling, Turning, Waterjet, Welding · ISO 9001, AS9100 | Shawnee, OK | MillingTurningWaterjetWelding | ISO 9001, AS9100 |
| Coast Metal Cutting Turning | San Jose, CA | Turning | - |
| Colburn Manufacturing Company Milling, Turning · ISO 9001, ISO 13485 | Fridley, MN | MillingTurning | ISO 9001, ISO 13485 |
| Colonial Welding, LLC Turning, Laser, Bending, Welding, Finishing | Norfolk, VA | TurningLaserBendingWeldingFinishing | - |
| Colorado Machine Works, Inc. Milling, Turning | Colorado Springs, CO | MillingTurning | - |
| 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 | - |
| 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 | - |
| Competitive Engineering, Inc Milling, Turning, EDM, Grinding, Assembly · AS9100 | Tucson, AZ | MillingTurningEDMGrindingAssembly | AS9100 |
| Component Products Corp Milling, Turning, Waterjet, Punching, Bending, Stamping, Assembly · AS9100, ITAR, CMMC | Mukilteo, WA | MillingTurningWaterjetPunchingBendingStampingAssembly | AS9100, ITAR, CMMC |
| 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 | - |
| Connecta Corp Milling, Turning, Swiss | Indianapolis, IN | MillingTurningSwiss | - |
| 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 |
| Conti Tool & Die, Inc Milling, Turning, Bending, Welding, Grinding | Akron, OH | MillingTurningBendingWeldingGrinding | - |
| Continental Machining Co Milling, Turning, Welding, EDM | Albuquerque, NM | MillingTurningWeldingEDM | - |
| Conturo Prototyping, LLC Milling, Turning | Pittsburgh, PA | MillingTurning | - |
| Copen Machine, Inc Milling, Turning, Swiss, Welding, Grinding · ISO 9001 | Kent, OH | MillingTurningSwissWeldingGrinding | ISO 9001 |
| 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 |
| CPK Manufacturing Milling, Turning, EDM · ISO 9001 | San Jose, CA | MillingTurningEDM | ISO 9001 |
| Craftco Metals Services Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Finishing, Assembly | Sheridan, WY | MillingTurningLaserWaterjetBendingWeldingFinishingAssembly | - |
| Creed Monarch Milling, Turning, Grinding · ISO 9001 | New Britain, CT | MillingTurningGrinding | ISO 9001 |
| Criterion Manufacturing Turning, Welding | Waterloo, IA | TurningWelding | - |
| Criterion Precision Machining Milling, Turning · ISO 9001, AS9100 | Cleveland, OH | MillingTurning | ISO 9001, AS9100 |
| Crown Machine Inc Milling, Turning, Welding, EDM · ISO 9001 | Rockford, IL | MillingTurningWeldingEDM | ISO 9001 |
| CTC Machining, LLC Milling, Turning | Hampstead, MD | MillingTurning | - |
| Cubitek, Inc Milling, Turning, EDM, Grinding · ISO 9001, AS9100 | Brentwood, NY | MillingTurningEDMGrinding | ISO 9001, AS9100 |
| Cumberland Machine Co Milling, Turning, Welding | Nashville, TN | MillingTurningWelding | - |
| Cunningham Machine Co Milling, Turning · ISO 9001, AS9100, ITAR | Chelmsford, MA | MillingTurning | ISO 9001, AS9100, ITAR |
| Curry Precision Machining LLC Milling, Turning | Winchester, CA | MillingTurning | - |
| Custom Aerospace Milling, Turning, Welding, EDM, Finishing, Assembly | Palm Bay, FL | MillingTurningWeldingEDMFinishingAssembly | - |
| Cut- Out Creations Milling, Turning, Welding | Rochester, NY | MillingTurningWelding | - |
| Cutco Metal Sawing LLC Milling, Turning, Welding, Grinding | Burleson, TX | MillingTurningWeldingGrinding | - |
| Cutter Innovations, LLC Milling, Turning, EDM · AS9100 | Wheat Ridge, CO | MillingTurningEDM | AS9100 |
| Cutting Edge Manufacturing Milling, Turning, Assembly · ISO 9001, AS9100 | Newbury Park, CA | MillingTurningAssembly | ISO 9001, AS9100 |
| Cutting Solutions Turning, Laser, Waterjet, Bending, Welding, Grinding, Finishing, Assembly | Zeeland, MI | TurningLaserWaterjetBendingWeldingGrindingFinishingAssembly | - |
| CV International, Inc Milling, Turning, Laser, Punching, Bending, Welding · ISO 9001 | Bend, OR | MillingTurningLaserPunchingBendingWelding | ISO 9001 |
| Cyclefab, LLC Milling, Turning, Welding | Renton, WA | MillingTurningWelding | - |
| D & D Automation Inc Milling, Turning, Welding, EDM | Terre Haute, IN | MillingTurningWeldingEDM | - |
| D & D Manufacturing LLC Milling, Turning, Grinding | Ipswich, MA | MillingTurningGrinding | - |
| D & G Manufacturing LLC Milling, Turning, Welding | Aurora, CO | MillingTurningWelding | - |
| David Packard Company, Inc Milling, Turning, Swiss, Grinding, Finishing, Assembly · ISO 9001, ITAR | Oxford, MA | MillingTurningSwissGrindingFinishingAssembly | ISO 9001, ITAR |
| Davis Industries Milling, Turning, Punching, Bending, Welding, Assembly · ISO 9001, AS9100 | Phoenix, AZ | MillingTurningPunchingBendingWeldingAssembly | ISO 9001, AS9100 |
| Davis Machine Mfg Co Turning | Euless, TX | Turning | - |
| Davis Tool & Die, Inc Milling, Turning, Welding, Stamping, EDM, Grinding | Abbeville, MS | MillingTurningWeldingStampingEDMGrinding | - |