| American Machining Inc Milling, Turning, Welding, Grinding, Finishing · ISO 9001 | Ottawa, IL | MillingTurningWeldingGrindingFinishing | ISO 9001 |
| Abbate Screw Products Inc Milling, Swiss, Grinding | Roselle, IL | MillingSwissGrinding | - |
| Betts Precision, Inc Milling, Turning, EDM, Grinding · AS9100, ISO 13485 | Alsip, IL | MillingTurningEDMGrinding | AS9100, ISO 13485 |
| Burns Machine Co Milling, Turning, Bending, Welding, Grinding, Assembly · ISO 9001 | Ottawa, IL | MillingTurningBendingWeldingGrindingAssembly | ISO 9001 |
| Camcraft Inc Milling, Turning, Grinding | Hanover Park, IL | MillingTurningGrinding | - |
| Center Tool Co Milling, Turning, Welding, Stamping, EDM, Grinding · ISO 9001 | Hampshire, IL | MillingTurningWeldingStampingEDMGrinding | ISO 9001 |
| E. J. Basler Co Milling, Turning, Swiss, Grinding · ISO 9001 | Schiller Park, IL | MillingTurningSwissGrinding | ISO 9001 |
| EDM Intelligent Solutions Milling, EDM, Grinding · ISO 9001, ITAR | Bartlett, IL | MillingEDMGrinding | ISO 9001, ITAR |
| Forster Tool & Manufacturing Co Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, AS9100, ITAR, CMMC | Bensenville, IL | MillingTurningSwissGrindingFinishing | ISO 9001, AS9100, ITAR, CMMC |
| Frey & Weiss Precision Machining Inc Milling, Turning, Grinding, Assembly · ISO 9001 | Wood Dale, IL | MillingTurningGrindingAssembly | ISO 9001 |
| Jacksonville Machine, Inc Milling, Turning, Welding, Grinding · ISO 9001 | Jacksonville, IL | MillingTurningWeldingGrinding | ISO 9001 |
| Kaskaskia Tool and Machine, Inc Milling, Turning, Bending, Welding, Stamping, EDM, Grinding · ISO 9001, AS9100 | New Athens, IL | MillingTurningBendingWeldingStampingEDMGrinding | ISO 9001, AS9100 |
| Ki Machine Tools & Productions Inc Milling, Turning, Bending, Welding, EDM, Grinding | Loves Park, IL | MillingTurningBendingWeldingEDMGrinding | - |
| Murphy Machine Products, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001 | Wood Dale, IL | MillingTurningSwissGrindingFinishing | ISO 9001 |
| Prototype & Production Co., Inc Milling, Turning, EDM, Grinding, Assembly · ISO 9001, ITAR | Wheeling, IL | MillingTurningEDMGrindingAssembly | ISO 9001, ITAR |
| Quadrant Tool and Manufacturing Company Milling, Turning, EDM, Grinding, Finishing | Schaumburg, IL | MillingTurningEDMGrindingFinishing | - |
| Sugar River Machine Inc Milling, Turning, Welding, Grinding, Finishing, Assembly | South Beloit, IL | MillingTurningWeldingGrindingFinishingAssembly | - |
| Surface Finishes Welding, Grinding · ITAR | Addison, IL | WeldingGrinding | ITAR |
| Systems Powered Manufacturing, LLC Grinding, Finishing, Assembly | Saint Charles, IL | GrindingFinishingAssembly | - |
| Taylor EDM Specialties LLC Milling, EDM, Grinding | Wauconda, IL | MillingEDMGrinding | - |
| Toolex Corp Milling, Welding, EDM, Grinding, Finishing | Addison, IL | MillingWeldingEDMGrindingFinishing | - |
| United Standard Industries Inc Milling, Turning, Welding, Grinding, Finishing · ISO 9001, AS9100 | Glenview, IL | MillingTurningWeldingGrindingFinishing | ISO 9001, AS9100 |
| Walco Tool & Engineering Corp Milling, Turning, Welding, Grinding, Finishing · ISO 9001 | Romeoville, IL | MillingTurningWeldingGrindingFinishing | ISO 9001 |