| Waltz Brothers, Inc Turning, Grinding · ISO 9001 | Wheeling, IL | TurningGrinding | ISO 9001 |
| Frey & Weiss Precision Machining Inc Milling, Turning, Grinding, Assembly · ISO 9001 | Wood Dale, IL | MillingTurningGrindingAssembly | ISO 9001 |
| 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 |
| Wesco Machine & Tool Turning, Laser, Welding, Grinding | Shorewood, IL | TurningLaserWeldingGrinding | - |
| Crown Machine Inc Milling, Turning, Welding, EDM · ISO 9001 | Rockford, IL | MillingTurningWeldingEDM | ISO 9001 |
| M-1 Tool Works, Inc Milling, Turning, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Mchenry, IL | MillingTurningEDMGrindingFinishingAssembly | ISO 9001, AS9100 |
| Magnum Steel Works Milling, Turning, Waterjet, Bending, Welding | Mount Vernon, IL | MillingTurningWaterjetBendingWelding | - |
| Swiss Automation, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR, ISO 13485 | Barrington, IL | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR, ISO 13485 |
| Wrightwood Precision Products Company Milling, Turning | Chicago, IL | MillingTurning | - |
| B T M Industries Inc Milling, Turning, Welding, Casting, Grinding | Woodstock, IL | MillingTurningWeldingCastingGrinding | - |
| DJW Assembly Inc Milling, Turning | Arlington Heights, IL | MillingTurning | - |
| Murphy Machine Products, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001 | Wood Dale, IL | MillingTurningSwissGrindingFinishing | ISO 9001 |
| Accumation Swiss Turning, Swiss · ISO 9001 | Crystal Lake, IL | TurningSwiss | ISO 9001 |
| Atlas Tool & Die Works Inc Turning, Laser, Waterjet, Welding, Stamping, EDM, Assembly | Lyons, IL | TurningLaserWaterjetWeldingStampingEDMAssembly | - |
| Prototype & Production Co., Inc Milling, Turning, EDM, Grinding, Assembly · ISO 9001, ITAR | Wheeling, IL | MillingTurningEDMGrindingAssembly | ISO 9001, ITAR |
| R & W Machine & Tool Works Milling, Turning · ISO 9001 | Chicago, IL | MillingTurning | ISO 9001 |
| Saliba Industries Milling, Turning, Grinding | Waukegan, IL | MillingTurningGrinding | - |
| Thomason Machine Works Inc Milling, Turning, EDM · ISO 9001 | Rockford, IL | MillingTurningEDM | ISO 9001 |
| 360 Machine Shop Milling, Turning, Laser, Welding, Metal AM | Bloomington, IL | MillingTurningLaserWeldingMetal AM | - |
| 425 Manufacturing Milling, Turning, Welding, EDM · ISO 9001 | Rockford, IL | MillingTurningWeldingEDM | ISO 9001 |
| 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 |
| Avanti Engineering Inc Milling, Turning, Swiss, EDM, Grinding, Finishing, Assembly · ISO 9001 | Glendale Heights, IL | MillingTurningSwissEDMGrindingFinishingAssembly | ISO 9001 |
| Bennett Metal Products Inc Milling, Turning, Waterjet, Welding · ISO 9001, ITAR | Mount Vernon, IL | MillingTurningWaterjetWelding | ISO 9001, ITAR |
| Burns Machine Co Milling, Turning, Bending, Welding, Grinding, Assembly · ISO 9001 | Ottawa, IL | MillingTurningBendingWeldingGrindingAssembly | ISO 9001 |
| 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 | - |
| Demco Products Milling, Turning, Swiss, Finishing, Assembly · ISO 9001 | Oak Lawn, IL | MillingTurningSwissFinishingAssembly | ISO 9001 |
| E. J. Basler Co Milling, Turning, Swiss, Grinding · ISO 9001 | Schiller Park, IL | MillingTurningSwissGrinding | ISO 9001 |
| Forge Resources Group Turning, Forging, Grinding, Finishing · ISO 9001, AS9100, ITAR | Dekalb, IL | TurningForgingGrindingFinishing | ISO 9001, AS9100, ITAR |
| Forster Tool & Manufacturing Co Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, AS9100, ITAR, CMMC | Bensenville, IL | MillingTurningSwissGrindingFinishing | ISO 9001, AS9100, ITAR, CMMC |
| General Machine Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Grinding, Finishing | Chicago, IL | MillingTurningLaserWaterjetPunchingBendingWeldingGrindingFinishing | - |
| Helander Metal Spinning Company LLC Milling, Turning, Laser, Waterjet, Welding, Stamping, EDM, Finishing · NADCAP | Lombard, IL | MillingTurningLaserWaterjetWeldingStampingEDMFinishing | NADCAP |
| 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 | - |
| LD Redmer Milling, Turning, Swiss, Welding, Finishing · ISO 9001, ITAR, NADCAP | Bensenville, IL | MillingTurningSwissWeldingFinishing | ISO 9001, ITAR, NADCAP |
| Magnum Machining LLC Milling, Turning, Finishing | Richmond, IL | MillingTurningFinishing | - |
| Manufacture Design Innovation, Inc Milling, Turning, Welding | Gilberts, IL | MillingTurningWelding | - |
| Mennie's Machine Co Milling, Turning, Welding, Grinding · IATF 16949 | Mark, IL | MillingTurningWeldingGrinding | IATF 16949 |
| Meyer Tool & Manufacturing, Inc Milling, Turning, Welding · ITAR | Oak Lawn, IL | MillingTurningWelding | ITAR |
| Minic Precision, Inc Turning, Swiss · ISO 9001 | Spring Grove, IL | TurningSwiss | ISO 9001 |
| Panek Precision Products LLC Milling, Turning, Stamping, Grinding, Finishing, Assembly · ITAR | Northbrook, IL | MillingTurningStampingGrindingFinishingAssembly | ITAR |
| Quadrant Tool and Manufacturing Company Milling, Turning, EDM, Grinding, Finishing | Schaumburg, IL | MillingTurningEDMGrindingFinishing | - |
| Quality Metal Products Inc Milling, Turning, Finishing | Peoria, IL | MillingTurningFinishing | - |
| Sanks Machining Inc Milling, Turning, Waterjet, Welding, EDM, Grinding | Staunton, IL | MillingTurningWaterjetWeldingEDMGrinding | - |
| Schmid Tool & Engineering Corp Milling, Turning, Swiss, Stamping, Grinding, Finishing, Assembly · ISO 9001, ITAR | Villa Park, IL | MillingTurningSwissStampingGrindingFinishingAssembly | ISO 9001, ITAR |