| Criterion Manufacturing Turning, Welding | Waterloo, IA | TurningWelding | - |
| Critical Components-Oil & Gas Milling, Turning, Welding, Metal AM, Finishing | Oklahoma City, OK | MillingTurningWeldingMetal AMFinishing | - |
| Critical Defense Inc Milling, Turning, Bending, Welding, Grinding, Assembly | Windber, PA | MillingTurningBendingWeldingGrindingAssembly | - |
| 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 Manufacturing & Polishing Inc Waterjet, Welding | Springfield, MO | WaterjetWelding | - |
| Custom Manufacturing Co Bending, Laser, Welding, Stamping · ISO 9001 | Dallas, TX | BendingLaserWeldingStamping | ISO 9001 |
| Custom Manufacturing Services, Inc Laser, Welding, Finishing, Assembly · ISO 9001 | Princeton, WV | LaserWeldingFinishingAssembly | ISO 9001 |
| Custom Metal Works Milling, Bending, Welding | Tulsa, OK | MillingBendingWelding | - |
| Custom Metalcraft Milling, Bending, Welding | Springfield, MO | MillingBendingWelding | - |
| Custom Tool & Model Corp Milling, Turning, Laser, Bending, Welding, Stamping, EDM, Grinding · ISO 9001, AS9100 | Frankfort, NY | MillingTurningLaserBendingWeldingStampingEDMGrinding | ISO 9001, AS9100 |
| 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 Manufacturing Milling, Bending, Welding · ISO 9001, AS9100 | Caldwell, ID | MillingBendingWelding | ISO 9001, AS9100 |
| Cutting Edge Solutions Mfg & Mro LLC Welding | Yuma, AZ | Welding | - |
| Cyclefab, LLC Milling, Turning, Welding | Renton, WA | MillingTurningWelding | - |
| D & D Design & Manufacturing Inc Milling, Turning, Bending, Laser, Welding | Oklahoma City, OK | MillingTurningBendingLaserWelding | - |
| DAD Manufacturing, Inc. Bending, Welding · ISO 9001 | Hiawatha, IA | BendingWelding | ISO 9001 |
| 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 |
| Damco, Inc Milling, Turning, Waterjet, Welding | New Bern, NC | MillingTurningWaterjetWelding | - |
| Dan's Custom Machining LLC Milling, Turning, Welding | Williamsburg, OH | MillingTurningWelding | - |
| Danco Precision, Inc Milling, Turning, Laser, Welding, Stamping, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Phoenixville, PA | MillingTurningLaserWeldingStampingEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| Dark Threat Fabrication LLC Milling, Turning, Laser, Bending, Welding, Finishing · ISO 9001 | Heber Springs, AR | MillingTurningLaserBendingWeldingFinishing | ISO 9001 |
| Davis Tool Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP | Hillsboro, OR | MillingTurningLaserWaterjetPunchingBendingWeldingEDMGrindingFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP |
| DCP Tool Manufacturing, LLC Milling, Turning, Laser, Welding, EDM, Grinding, Finishing | Dayton, OH | MillingTurningLaserWeldingEDMGrindingFinishing | - |
| Defelice Engineering, Inc Milling, Turning, Bending, Welding, Casting, Grinding | Mooresville, IN | MillingTurningBendingWeldingCastingGrinding | - |
| Defense & Aerospace Manufacturing LLC Welding, Grinding, Finishing, Assembly | Rancho Cordova, CA | WeldingGrindingFinishingAssembly | - |
| Delco LLC Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100 | Akron, OH | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100 |
| Delt Forge, Inc Milling, Turning, Welding, Forging, Grinding | Rose City, MI | MillingTurningWeldingForgingGrinding | - |
| Delta Hi-Tech Milling, Turning, Swiss, Laser, Bending, Welding, EDM, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP, ISO 13485 | Chatsworth, CA | MillingTurningSwissLaserBendingWeldingEDMFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP, ISO 13485 |
| Deltisan Engineering LLC Milling, Turning, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Parker, CO | MillingTurningPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Denver Machine Shop Milling, Turning, Welding · ISO 9001 | Henderson, CO | MillingTurningWelding | ISO 9001 |
| Des Moines Iron & Supply Co Bending, Welding | Des Moines, IA | BendingWelding | - |
| Des Moines Metal Fab Bending, Laser, Welding | Des Moines, IA | BendingLaserWelding | - |
| Desert Metal Works Bending, Laser, Welding, Waterjet | Tucson, AZ | BendingLaserWeldingWaterjet | - |
| Desert Precision Manufacturing Bending, Laser, Welding · ISO 9001 | Tucson, AZ | BendingLaserWelding | ISO 9001 |
| Diamond Manufacturing of Bluffton, Ltd Laser, Welding, Assembly | Bluffton, OH | LaserWeldingAssembly | - |
| Dimark Precision Machining,, Inc Milling, Turning, Welding, Grinding | Pembroke, MA | MillingTurningWeldingGrinding | - |
| Dixon Tool & Die Co Inc Milling, Turning, Waterjet, Welding, EDM, Grinding · ISO 9001, CMMC | Tyrone, PA | MillingTurningWaterjetWeldingEDMGrinding | ISO 9001, CMMC |
| Dms-South/bailey Tool LLC Milling, Turning, Welding, Stamping, EDM | Lancaster, TX | MillingTurningWeldingStampingEDM | - |
| Dominguez Sheet Metal Works, Inc Welding | El Paso, TX | Welding | - |
| Donsco, Inc Milling, Welding, Casting | Wrightsville, PA | MillingWeldingCasting | - |
| Douglas Machine & Engineering Milling, Turning, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, CMMC | Davenport, IA | MillingTurningBendingWeldingEDM | ISO 9001, AS9100, ITAR, CMMC |
| Draeving Machine Tool, Inc Milling, Turning, Welding, EDM | Beloit, WI | MillingTurningWeldingEDM | - |
| DW Engineering LLC Milling, Turning, Welding | Burnsville, MN | MillingTurningWelding | - |
| Dynamic Marine Machining Welding | Spring Valley, CA | Welding | - |
| Dynamic Sheetmetal Fabrication, LLC Bending, Welding · ISO 9001 | St Paul, MN | BendingWelding | ISO 9001 |
| E.H. Schwab Milling, Turning, Laser, Punching, Bending, Welding · ISO 9001 | Turtle Creek, PA | MillingTurningLaserPunchingBendingWelding | ISO 9001 |