| Concise Manufacturing Inc Milling, Turning, Welding, EDM | Salisbury, NC | MillingTurningWeldingEDM | - |
| Conturo Prototyping, LLC Milling, Turning | Pittsburgh, PA | MillingTurning | - |
| Copen Machine, Inc Milling, Turning, Swiss, Welding, Grinding · ISO 9001 | Kent, OH | MillingTurningSwissWeldingGrinding | ISO 9001 |
| Core-X LLC Laser, Welding | Commerce City, CO | LaserWelding | - |
| Coronado Steel Co Turning, Welding, Casting, Metal AM | Youngstown, OH | TurningWeldingCastingMetal AM | - |
| Creative Metal Products Inc Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Neenah, WI | PunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Criterion Precision Machining Milling, Turning · ISO 9001, AS9100 | Cleveland, OH | MillingTurning | ISO 9001, AS9100 |
| CS Tool Engineering, Inc Milling, Welding | Cedar Springs, MI | MillingWelding | - |
| Cte Machine Inc Milling, Turning, Finishing | Groveland, FL | MillingTurningFinishing | - |
| Custom Machine Milling, Turning, Welding, Grinding | Hagerstown, MD | MillingTurningWeldingGrinding | - |
| Custom Manufacturing Co Bending, Laser, Welding, Stamping · ISO 9001 | Dallas, TX | BendingLaserWeldingStamping | ISO 9001 |
| Custom Metalcraft Milling, Bending, Welding | Springfield, MO | MillingBendingWelding | - |
| Cutting Edge Manufacturing Milling, Turning, Assembly · ISO 9001, AS9100 | Newbury Park, CA | MillingTurningAssembly | ISO 9001, AS9100 |
| D & G Manufacturing LLC Milling, Turning, Welding | Aurora, CO | MillingTurningWelding | - |
| D. J. Fabricators, Inc Milling, Laser, Waterjet, Punching, Bending, Welding, EDM, Grinding, Assembly · ISO 9001 | Ipswich, MA | MillingLaserWaterjetPunchingBendingWeldingEDMGrindingAssembly | ISO 9001 |
| D&T Dynamics LLC Milling | Hyrum, UT | Milling | - |
| Daico Precision LLC Milling, Turning, Grinding, Finishing, Assembly | Garden Grove, CA | MillingTurningGrindingFinishingAssembly | - |
| Dallas Metal Fabricators Inc. Laser, Welding | Dallas, TX | LaserWelding | - |
| Dark Threat Fabrication LLC Milling, Turning, Laser, Bending, Welding, Finishing · ISO 9001 | Heber Springs, AR | MillingTurningLaserBendingWeldingFinishing | ISO 9001 |
| Data Electronic Services Finishing · ISO 9001, ITAR | Santa Ana, CA | Finishing | ISO 9001, ITAR |
| Davis Machine Mfg Co Turning | Euless, TX | Turning | - |
| Davis Tool & Die, Inc Milling, Turning, Welding, Stamping, EDM, Grinding | Abbeville, MS | MillingTurningWeldingStampingEDMGrinding | - |
| Decker Machine Works Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001, AS9100, ITAR | Greenfield, MA | MillingTurningSwissEDMGrinding | ISO 9001, AS9100, ITAR |
| Delflo Industries Inc Milling, Turning, Waterjet, Bending, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR, ISO 13485, CMMC | Delray Beach, FL | MillingTurningWaterjetBendingWeldingEDMGrindingAssembly | ISO 9001, AS9100, ITAR, ISO 13485, CMMC |
| Delta One Manufacturing LLC Milling, Turning, Laser, Welding, Finishing, Assembly | San Jose, CA | MillingTurningLaserWeldingFinishingAssembly | - |
| Des Moines Metal Fab Bending, Laser, Welding | Des Moines, IA | BendingLaserWelding | - |
| Desemco, LLC Milling, Turning, Laser · AS9100 | Marietta, GA | MillingTurningLaser | AS9100 |
| Dessureau Machines Inc Milling, Turning, Welding | Berlin, VT | MillingTurningWelding | - |
| Deval Life Cycle Support LLC Milling, Turning, Welding, Assembly · ISO 9001, AS9100 | Philadelphia, PA | MillingTurningWeldingAssembly | ISO 9001, AS9100 |
| Dexter Design & Development Co Milling, Turning, EDM, Grinding, Assembly · ISO 9001 | Hillsboro, OR | MillingTurningEDMGrindingAssembly | ISO 9001 |
| Dieform LLC Turning, Punching, Bending, Grinding · ISO 9001, NADCAP | Jurupa Valley, CA | TurningPunchingBendingGrinding | ISO 9001, NADCAP |
| Dinucci Corp Milling, Turning · AS9100 | Concord, CA | MillingTurning | AS9100 |
| Diversified Machining Inc Milling, Welding | Forest Hill, MD | MillingWelding | - |
| DP Products, Inc Milling, Turning, EDM · ISO 9001 | San Jose, CA | MillingTurningEDM | ISO 9001 |
| Draeving Machine Tool, Inc Milling, Turning, Welding, EDM | Beloit, WI | MillingTurningWeldingEDM | - |
| DRM Industries Corp Milling, Turning, Laser, Welding, Casting · ISO 9001 | Lake Delton, WI | MillingTurningLaserWeldingCasting | ISO 9001 |
| DRP Machine Milling, Turning, Grinding · ISO 9001 | West Valley City, UT | MillingTurningGrinding | ISO 9001 |
| DT Precision, LLC Milling, Turning, Swiss · ISO 9001, AS9100, ITAR, ISO 13485 | San Jose, CA | MillingTurningSwiss | ISO 9001, AS9100, ITAR, ISO 13485 |
| Dynacut Manufacturing LLC Milling, Turning, Swiss, Finishing · ISO 9001 | Lees Summit, MO | MillingTurningSwissFinishing | ISO 9001 |
| Dynamic Balance Machine Milling, Turning · ISO 9001, AS9100, ITAR | Salt Lake City, UT | MillingTurning | ISO 9001, AS9100, ITAR |
| Dynamic Machine of Detroit Milling, Turning, Casting, Metal AM | Troy, MI | MillingTurningCastingMetal AM | - |
| E. J. Basler Co Milling, Turning, Swiss, Grinding · ISO 9001 | Schiller Park, IL | MillingTurningSwissGrinding | ISO 9001 |
| Eagle Magnetic Co Inc Laser, Welding, Finishing · ISO 9001 | Indianapolis, IN | LaserWeldingFinishing | ISO 9001 |
| Echo Talents LLC EDM, Finishing · ISO 9001, AS9100, ITAR, CMMC | Dripping Spgs, TX | EDMFinishing | ISO 9001, AS9100, ITAR, CMMC |
| Edco Engineering Inc Milling, Bending, Welding · ISO 9001, AS9100, NADCAP | Newington, CT | MillingBendingWelding | ISO 9001, AS9100, NADCAP |
| Ejays Machine Co Inc Milling, Bending, Assembly · ISO 9001, AS9100 | Fullerton, CA | MillingBendingAssembly | ISO 9001, AS9100 |
| El Ironworks LLC Bending, Welding, Finishing · ISO 9001 | Toney, AL | BendingWeldingFinishing | ISO 9001 |
| Elemental Design & Machinery, LLC Milling | Chattanooga, TN | Milling | - |
| Elite Machine, Inc Milling, Turning | Manchester, NY | MillingTurning | - |
| Elite Turning & Machining Corp Milling, Turning, EDM, Casting · AS9100 | Rochester, NY | MillingTurningEDMCasting | AS9100 |