| Classic Engineering, LLC Milling, Turning, Waterjet, Welding, Finishing | Gloucester, MA | MillingTurningWaterjetWeldingFinishing | - |
| Classic Machine & Engineering Milling, Turning, Laser, Welding, Grinding | Ashland, VA | MillingTurningLaserWeldingGrinding | - |
| Clint Precision Manufacturing Milling, Turning, Welding, Waterjet · ISO 9001 | San Diego, CA | MillingTurningWeldingWaterjet | ISO 9001 |
| CNC Machine and Fabrication, Inc Laser, Waterjet, Punching, Bending, Welding, Stamping, Grinding, Finishing | Hyde Park, UT | LaserWaterjetPunchingBendingWeldingStampingGrindingFinishing | - |
| CNC Specialties Manufacturing Inc Milling, Turning, Bending, Welding, EDM, Grinding, Finishing | Apollo, PA | MillingTurningBendingWeldingEDMGrindingFinishing | - |
| CNC Syndicate Welding | Ravenswood, WV | Welding | - |
| Coanda Company LLC, the Milling, Turning, Waterjet, Welding · ISO 9001, AS9100 | Shawnee, OK | MillingTurningWaterjetWelding | ISO 9001, AS9100 |
| Colleen & Herb Enterprises Inc Milling, Turning, Welding | Fremont, CA | MillingTurningWelding | - |
| Collins Machine Works Welding, Grinding · CMMC | Portsmouth, VA | WeldingGrinding | CMMC |
| Columbus Machine Works Milling, Turning, Bending, Welding, EDM, Casting | Columbus, OH | MillingTurningBendingWeldingEDMCasting | - |
| Combs Enterprises Incorporated Milling, Turning, Bending, Welding, Finishing · ITAR | Great Mills, MD | MillingTurningBendingWeldingFinishing | ITAR |
| Comet Fabricating & Welding Co Laser, Bending, Welding | Rockford, IL | LaserBendingWelding | - |
| Commercial Tool & Die Inc Milling, Turning, Welding, Grinding | Marshall, VA | MillingTurningWeldingGrinding | - |
| Compo Engineering LLC Welding, Finishing | Westport, CT | WeldingFinishing | - |
| 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 |
| Conner Brothers Machine Co., Inc Milling, Turning, Welding, Grinding · ISO 9001 | Bessemer City, NC | MillingTurningWeldingGrinding | ISO 9001 |
| 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 | - |
| Contract Machining Milling, Turning, Welding · ISO 9001 | Lexington, KY | MillingTurningWelding | ISO 9001 |
| 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 | - |
| Cortec Precision Sheetmetal Milling, Turning, Bending, Laser, Welding | San Jose, CA | MillingTurningBendingLaserWelding | - |
| Council Stainless & Sheet Metal Bending, Welding, Waterjet | Oklahoma City, OK | BendingWeldingWaterjet | - |
| Coventry Industries LLC Waterjet, Welding, EDM · ITAR | Holly, MI | WaterjetWeldingEDM | ITAR |
| CP Industries Inc Milling, Welding, Casting | Granger, IN | MillingWeldingCasting | - |
| Creative Machining Solutions Welding, Finishing | Walford, IA | WeldingFinishing | - |
| Creative Machining Systems Inc Milling, Turning, Welding, EDM, Grinding, Finishing | Trenton, NJ | MillingTurningWeldingEDMGrindingFinishing | - |
| Criterion Manufacturing Turning, Welding | Waterloo, IA | TurningWelding | - |
| Critical Defense Inc Milling, Turning, Bending, Welding, Grinding, Assembly | Windber, PA | MillingTurningBendingWeldingGrindingAssembly | - |
| Crown Fabricators Welding | Las Vegas, NV | Welding | - |
| Crown Machine Inc Milling, Turning, Welding, EDM · ISO 9001 | Rockford, IL | MillingTurningWeldingEDM | ISO 9001 |
| Cuddeback Machining, Inc Milling, Turning, Laser, Welding, Stamping, EDM, Grinding · ISO 9001 | Hilton, NY | MillingTurningLaserWeldingStampingEDMGrinding | ISO 9001 |
| Cuevas Machine Co., Inc Welding | Poplarville, MS | Welding | - |
| Custom Machine Milling, Turning, Welding, Grinding | Hagerstown, MD | MillingTurningWeldingGrinding | - |
| Custom Machine & Design Inc Milling, Turning, Waterjet, Welding, EDM, Grinding | Lincoln, NE | MillingTurningWaterjetWeldingEDMGrinding | - |
| Custom Welding by Law, Inc Waterjet, Bending, Welding | Orlando, FL | WaterjetBendingWelding | - |
| Cut- Out Creations Milling, Turning, Welding | Rochester, NY | MillingTurningWelding | - |
| Cutco Metal Sawing LLC Milling, Turning, Welding, Grinding | Burleson, TX | MillingTurningWeldingGrinding | - |
| Cutting Edge Fabrication Inc Milling, Bending, Laser, Welding · ISO 9001 | Milwaukee, WI | MillingBendingLaserWelding | ISO 9001 |
| Cutting Edge Fabrication LLC Welding | Tucson, AZ | Welding | - |
| Cutting Edge Manufacturing Milling, Bending, Welding · ISO 9001, AS9100 | Caldwell, ID | MillingBendingWelding | ISO 9001, AS9100 |
| Cutting Edge Solutions Mfg & Mro LLC Welding | Yuma, AZ | Welding | - |
| Cutting Solutions Turning, Laser, Waterjet, Bending, Welding, Grinding, Finishing, Assembly | Zeeland, MI | TurningLaserWaterjetBendingWeldingGrindingFinishingAssembly | - |
| Cutting Source Precision Milling, Turning, Bending, Welding, EDM, Stamping · ISO 9001 | Houston, TX | MillingTurningBendingWeldingEDMStamping | ISO 9001 |
| CV International, Inc Milling, Turning, Laser, Punching, Bending, Welding · ISO 9001 | Bend, OR | MillingTurningLaserPunchingBendingWelding | ISO 9001 |