| Coulter Forge, LLC Turning, Forging | Emeryville, CA | TurningForging | - |
| Council Stainless & Sheet Metal Bending, Welding, Waterjet | Oklahoma City, OK | BendingWeldingWaterjet | - |
| Cox Machine LLC Milling, Turning, Welding, EDM, Grinding, Finishing · ISO 9001, ITAR | Traverse City, MI | MillingTurningWeldingEDMGrindingFinishing | ISO 9001, ITAR |
| Cox Manufacturing Co Milling, Turning, Swiss, EDM · ISO 9001, ITAR | San Antonio, TX | MillingTurningSwissEDM | ISO 9001, ITAR |
| CP Industries Inc Milling, Welding, Casting | Granger, IN | MillingWeldingCasting | - |
| Creative Custom Products Milling, Welding | Phoenix, AZ | MillingWelding | - |
| Creative Metal Products Inc Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Neenah, WI | PunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Cross Machine, Inc Assembly | Berlin, NH | Assembly | - |
| Crown Fabricators Welding | Las Vegas, NV | Welding | - |
| CS Tool Engineering, Inc Milling, Welding | Cedar Springs, MI | MillingWelding | - |
| Csi Manufacturing Inc Milling, Turning, Laser, Welding, Stamping, Finishing · ISO 9001 | Westborough, MA | MillingTurningLaserWeldingStampingFinishing | ISO 9001 |
| Cubitek, Inc Milling, Turning, EDM, Grinding · ISO 9001, AS9100 | Brentwood, NY | MillingTurningEDMGrinding | ISO 9001, AS9100 |
| Cuevas Machine Co., Inc Welding | Poplarville, MS | Welding | - |
| 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 Engineering Co Milling, Turning, Bending, Welding · ISO 9001, ITAR, NADCAP | Erie, PA | MillingTurningBendingWelding | ISO 9001, ITAR, NADCAP |
| Custom Laser Works LLC Laser, Bending, Welding | Addison, IL | LaserBendingWelding | - |
| Custom Machine Milling, Turning, Welding, Grinding | Hagerstown, MD | MillingTurningWeldingGrinding | - |
| Custom Machine & Design Inc Milling, Turning, Waterjet, Welding, EDM, Grinding | Lincoln, NE | MillingTurningWaterjetWeldingEDMGrinding | - |
| Custom Machine Inc Milling, Turning, EDM · ISO 9001, AS9100, ITAR, ISO 13485, NADCAP | Woburn, MA | MillingTurningEDM | ISO 9001, AS9100, ITAR, ISO 13485, NADCAP |
| Custom Manufacturing Services, Inc Laser, Welding, Finishing, Assembly · ISO 9001 | Princeton, WV | LaserWeldingFinishingAssembly | ISO 9001 |
| Custom Metal Fabricators Milling, Bending, Laser, Welding | Richmond, VA | MillingBendingLaserWelding | - |
| Custom Metal Works Milling, Bending, Welding | Tulsa, OK | MillingBendingWelding | - |
| Custom Tool & Model Corp Milling, Turning, Laser, Bending, Welding, Stamping, EDM, Grinding · ISO 9001, AS9100 | Frankfort, NY | MillingTurningLaserBendingWeldingStampingEDMGrinding | ISO 9001, AS9100 |
| Custom Tool Inc Milling, Swiss · ISO 9001 | Cookeville, TN | MillingSwiss | ISO 9001 |
| 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 Machining & Automation-Qtr, LLC Milling, Turning, Swiss, Laser, Welding, EDM, Assembly | North Versailles, PA | MillingTurningSwissLaserWeldingEDMAssembly | - |
| 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 |
| Cyclefab, LLC Milling, Turning, Welding | Renton, WA | MillingTurningWelding | - |
| D & D Automation Inc Milling, Turning, Welding, EDM | Terre Haute, IN | MillingTurningWeldingEDM | - |
| D & G Machine Products, LLC Milling, Turning, Bending, Laser, Welding · ISO 9001, AS9100 | Gorham, ME | MillingTurningBendingLaserWelding | ISO 9001, AS9100 |
| D & H Industries Inc Milling, Turning, Laser, Bending, Welding, Stamping, Grinding, Finishing · ISO 9001, ITAR | Oconomowoc, WI | MillingTurningLaserBendingWeldingStampingGrindingFinishing | ISO 9001, ITAR |
| D & S Manufacturing, Inc Milling, Turning, Assembly · ISO 9001, ITAR | Wichita, KS | MillingTurningAssembly | ISO 9001, ITAR |
| D. J. Fabricators, Inc Milling, Laser, Waterjet, Punching, Bending, Welding, EDM, Grinding, Assembly · ISO 9001 | Ipswich, MA | MillingLaserWaterjetPunchingBendingWeldingEDMGrindingAssembly | ISO 9001 |
| D.P. Tool Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Avon, NY | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| D&D Enterprises of Greensboro Inc Milling, Turning, Swiss, Assembly · ISO 9001, AS9100 | Randleman, NC | MillingTurningSwissAssembly | ISO 9001, AS9100 |
| D&J Technologies Inc. Milling, Turning · ISO 9001, AS9100 | Fort Worth, TX | MillingTurning | ISO 9001, AS9100 |
| DAD Manufacturing, Inc. Bending, Welding · ISO 9001 | Hiawatha, IA | BendingWelding | ISO 9001 |
| Daico Precision LLC Milling, Turning, Grinding, Finishing, Assembly | Garden Grove, CA | MillingTurningGrindingFinishingAssembly | - |
| Dallas Metal Fabricators Inc. Laser, Welding | Dallas, TX | LaserWelding | - |
| Dallas Precision Machining Milling, Turning, Bending, Laser, Welding, Waterjet, Metal AM · ISO 9001, AS9100, ITAR | Carrollton, TX | MillingTurningBendingLaserWeldingWaterjetMetal AM | ISO 9001, AS9100, ITAR |
| Danser, Inc Milling, Laser, Punching, Bending, Welding | Davisville, WV | MillingLaserPunchingBendingWelding | - |
| David Packard Company, Inc Milling, Turning, Swiss, Grinding, Finishing, Assembly · ISO 9001, ITAR | Oxford, MA | MillingTurningSwissGrindingFinishingAssembly | ISO 9001, ITAR |
| Davis Machine Mfg Co Turning | Euless, TX | Turning | - |
| Davis Machine Works of Opelika Inc Welding | Opelika, AL | Welding | - |
| Davis Manufacturing Co Milling, Turning, Welding, Finishing · AS9100, ITAR, CMMC | Wheat Ridge, CO | MillingTurningWeldingFinishing | AS9100, ITAR, CMMC |