| Abbate Screw Products Inc Milling, Swiss, Grinding | Roselle, IL | MillingSwissGrinding | - |
| Ace of Diamonds International Inc Milling | Aurora, IL | Milling | - |
| Acme Industries, Inc Milling, Turning, Welding, Casting · ISO 9001, AS9100 | Elk Grove Village, IL | MillingTurningWeldingCasting | ISO 9001, AS9100 |
| American Machining Inc Milling, Turning, Welding, Grinding, Finishing · ISO 9001 | Ottawa, IL | MillingTurningWeldingGrindingFinishing | ISO 9001 |
| Art CNC Machining LLC Milling, Turning, Assembly · ISO 9001 | Bridgeview, IL | MillingTurningAssembly | ISO 9001 |
| Bland Brothers Enterprises Milling, Welding, Assembly | Springfield, IL | MillingWeldingAssembly | - |
| Calisota Parts, LLC Milling, Waterjet, Stamping, EDM | Frankfort, IL | MillingWaterjetStampingEDM | - |
| Carr Machine & Tool, Inc Milling, Grinding, Assembly · ISO 9001, ITAR, CMMC | Elk Grove Village, IL | MillingGrindingAssembly | ISO 9001, ITAR, CMMC |
| Center Tool Co Milling, Turning, Welding, Stamping, EDM, Grinding · ISO 9001 | Hampshire, IL | MillingTurningWeldingStampingEDMGrinding | ISO 9001 |
| Century Metal Spinning Co Milling, Turning, Laser, Bending, Welding, Finishing · ISO 9001, AS9100, ITAR | Bensenville, IL | MillingTurningLaserBendingWeldingFinishing | ISO 9001, AS9100, ITAR |
| Chicago CNC Machining Co. Milling, Turning, Bending, Welding | Hodgkins, IL | MillingTurningBendingWelding | - |
| CM Fabrication, LLC Milling, Laser, Welding, Finishing | Sycamore, IL | MillingLaserWeldingFinishing | - |
| E. J. Basler Co Milling, Turning, Swiss, Grinding · ISO 9001 | Schiller Park, IL | MillingTurningSwissGrinding | ISO 9001 |
| Forster Tool & Manufacturing Co Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, AS9100, ITAR, CMMC | Bensenville, IL | MillingTurningSwissGrindingFinishing | ISO 9001, AS9100, ITAR, CMMC |
| General Machinery & Manufacturing Co Milling, Turning, Bending, Stamping · ISO 9001, AS9100 | Chicago, IL | MillingTurningBendingStamping | ISO 9001, AS9100 |
| Ki Machine Tools & Productions Inc Milling, Turning, Bending, Welding, EDM, Grinding | Loves Park, IL | MillingTurningBendingWeldingEDMGrinding | - |
| Pegasus Mfg Inc Milling, Turning, Metal AM · ISO 9001, AS9100 | Galesburg, IL | MillingTurningMetal AM | ISO 9001, AS9100 |
| Prototype & Production Co., Inc Milling, Turning, EDM, Grinding, Assembly · ISO 9001, ITAR | Wheeling, IL | MillingTurningEDMGrindingAssembly | ISO 9001, ITAR |
| Schmid Tool & Engineering Corp Milling, Turning, Swiss, Stamping, Grinding, Finishing, Assembly · ISO 9001, ITAR | Villa Park, IL | MillingTurningSwissStampingGrindingFinishingAssembly | ISO 9001, ITAR |
| Stanley Machining & Tool Corp Milling, Turning · ISO 9001 | Carpentersville, IL | MillingTurning | ISO 9001 |
| The Bennu Group Inc Milling, Turning, Waterjet, Welding, Finishing · ISO 9001 | South Holland, IL | MillingTurningWaterjetWeldingFinishing | ISO 9001 |
| Toolex Corp Milling, Welding, EDM, Grinding, Finishing | Addison, IL | MillingWeldingEDMGrindingFinishing | - |
| Wagner Machine Company Milling, Turning, Swiss, Waterjet, Metal AM, EDM | Champaign, IL | MillingTurningSwissWaterjetMetal AMEDM | - |
| Walco Tool & Engineering Corp Milling, Turning, Welding, Grinding, Finishing · ISO 9001 | Romeoville, IL | MillingTurningWeldingGrindingFinishing | ISO 9001 |
| Wpa Works LLC Milling, Turning, Swiss, EDM, Finishing · ISO 9001 | Elgin, IL | MillingTurningSwissEDMFinishing | ISO 9001 |