| Quadrant Tool and Manufacturing Company Milling, Turning, EDM, Grinding, Finishing | Schaumburg, IL | MillingTurningEDMGrindingFinishing | - |
| Qualitask Inc Milling, Turning, Swiss, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Anaheim, CA | MillingTurningSwissWeldingEDMGrindingFinishingAssembly | ISO 9001, AS9100 |
| Quality Controlled Manufacturing Inc Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100, ITAR, NADCAP | Santee, CA | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100, ITAR, NADCAP |
| Quality Engineering Services Inc Milling, Turning, Welding, EDM, Grinding · ISO 9001, ITAR | Wallingford, CT | MillingTurningWeldingEDMGrinding | ISO 9001, ITAR |
| R. J. Zeman Tool & Mfg. Co., Inc Milling, Turning, Welding, Casting, EDM, Grinding · ISO 9001, ITAR | Waukesha, WI | MillingTurningWeldingCastingEDMGrinding | ISO 9001, ITAR |
| R.M. Baker Machine & Tool, Inc Milling, Welding, EDM, Grinding, Finishing | Covina, CA | MillingWeldingEDMGrindingFinishing | - |
| Range Precision Milling, Turning, EDM, Grinding, Finishing | Blaine, MN | MillingTurningEDMGrindingFinishing | - |
| Raptor Manufacturing LC Milling, Turning, Welding, Grinding · ISO 9001, AS9100, ITAR | Wichita, KS | MillingTurningWeldingGrinding | ISO 9001, AS9100, ITAR |
| RB Industrial Manufacturer LLC Milling, Swiss, Grinding | Racine, WI | MillingSwissGrinding | - |
| RB Machining, Inc Milling, Turning, Grinding · AS9100 | Palmdale, CA | MillingTurningGrinding | AS9100 |
| Red Lion Inc Laser, Grinding · AS9100 | Broomfield, CO | LaserGrinding | AS9100 |
| Resivine LLC Milling, Turning, Waterjet, EDM, Grinding | Houston, TX | MillingTurningWaterjetEDMGrinding | - |
| Revolution Precision Machining LLC Swiss, Grinding, Finishing · ISO 9001, AS9100 | Tulsa, OK | SwissGrindingFinishing | ISO 9001, AS9100 |
| Reynolda Manufacturing Solutions, Inc Milling, Welding, EDM, Grinding · ISO 9001 | East Bend, NC | MillingWeldingEDMGrinding | ISO 9001 |
| Rig Machine Works LLC Milling, Turning, Bending, Welding, Grinding | Stevensville, MT | MillingTurningBendingWeldingGrinding | - |
| Riley Gear Grinding | Saint Augustine, FL | Grinding | - |
| RMT Corporation Milling, Turning, Welding, Grinding | Dayton, OH | MillingTurningWeldingGrinding | - |
| Rocktech Milling, Grinding | Chesterfield, MI | MillingGrinding | - |
| Ruhl Inc Milling, Turning, Waterjet, Welding, Grinding | Spring Lake, NC | MillingTurningWaterjetWeldingGrinding | - |
| S & S Die Co Milling, Turning, Welding, EDM, Grinding | Lansing, MI | MillingTurningWeldingEDMGrinding | - |
| S & S Tool & Machine Co Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100, ITAR | Louisville, KY | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100, ITAR |
| Saliba Industries Milling, Turning, Grinding | Waukegan, IL | MillingTurningGrinding | - |
| Sanks Machining Inc Milling, Turning, Waterjet, Welding, EDM, Grinding | Staunton, IL | MillingTurningWaterjetWeldingEDMGrinding | - |
| Santa Lucia Manufacturing, Inc Milling, Turning, Grinding | Atascadero, CA | MillingTurningGrinding | - |
| Schaefer Screw Products Co Milling, Turning, Grinding, Finishing | Garden City, MI | MillingTurningGrindingFinishing | - |
| Schmid Tool & Engineering Corp Milling, Turning, Swiss, Stamping, Grinding, Finishing, Assembly · ISO 9001, ITAR | Villa Park, IL | MillingTurningSwissStampingGrindingFinishingAssembly | ISO 9001, ITAR |
| Schmiede Corporation Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001 | Tullahoma, TN | MillingTurningWeldingEDMGrindingAssembly | ISO 9001 |
| Scientific Tool Milling, Turning, Grinding | Syracuse, NY | MillingTurningGrinding | - |
| SDS Engineering Milling, Turning, Grinding · ISO 9001 | Sun Valley, CA | MillingTurningGrinding | ISO 9001 |
| Sharp Dimension Inc Milling, Turning, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001, ITAR | Fremont, CA | MillingTurningBendingWeldingGrindingFinishingAssembly | ISO 9001, ITAR |
| Shrettech Tool & Machine LLC Milling, Turning, Welding, Grinding | Racine, WI | MillingTurningWeldingGrinding | - |
| Smith Metal, LLC Milling, Turning, Swiss, Laser, Waterjet, Bending, Welding, EDM, Grinding, Finishing · ISO 9001 | Augusta, MI | MillingTurningSwissLaserWaterjetBendingWeldingEDMGrindingFinishing | ISO 9001 |
| Sonic Aerospace Inc Milling, Turning, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Chandler, AZ | MillingTurningGrindingFinishingAssembly | ISO 9001, AS9100 |
| South Central Manufacturing Corp Milling, Turning, Welding, Grinding | Summersville, MO | MillingTurningWeldingGrinding | - |
| Southern Precision Machining Milling, Turning, Grinding, Finishing · ISO 9001, AS9100, ITAR | Shelbyville, TN | MillingTurningGrindingFinishing | ISO 9001, AS9100, ITAR |
| Specialty Roller and Machine Inc Milling, Turning, Grinding | Berwick, PA | MillingTurningGrinding | - |
| Specialty Tool & Die Company Inc Milling, Turning, Bending, Welding, Stamping, Grinding, Assembly | Kokomo, IN | MillingTurningBendingWeldingStampingGrindingAssembly | - |
| Spectrum Custom Molds & Manufacturing, Inc Milling, Turning, Laser, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Palmetto, FL | MillingTurningLaserWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Stanton Precision Products L.L.C Milling, Turning, Swiss, Grinding · CMMC | Butler, NJ | MillingTurningSwissGrinding | CMMC |
| Starlite Diversified Inc Milling, Turning, Welding, EDM, Grinding | Meadville, PA | MillingTurningWeldingEDMGrinding | - |
| Starn Tool & Manufacturing Company Milling, Turning, EDM, Grinding, Finishing · ISO 9001, ITAR | Meadville, PA | MillingTurningEDMGrindingFinishing | ISO 9001, ITAR |
| Stephen J Hartman Milling, Turning, Welding, Grinding | Sykesville, MD | MillingTurningWeldingGrinding | - |
| Stever Locke, Inc Turning, Stamping, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR | Honeoye Falls, NY | TurningStampingGrindingFinishingAssembly | ISO 9001, AS9100, ITAR |
| Stone Machine Co. Inc Milling, Turning, Grinding, Finishing | Chester, NH | MillingTurningGrindingFinishing | - |
| Stork Precision Machining LLC Milling, Turning, Welding, EDM, Grinding · ISO 9001, CMMC | Washington, MO | MillingTurningWeldingEDMGrinding | ISO 9001, CMMC |
| Streamline Machine Source Inc Milling, Laser, Waterjet, Grinding · ISO 9001 | Greenville, MI | MillingLaserWaterjetGrinding | ISO 9001 |
| Sturdy Grinding & Machining Inc Grinding, Finishing · ISO 9001 | New Haven, MI | GrindingFinishing | ISO 9001 |
| Sulzer Machine & Manufacturing Inc Milling, Welding, Grinding · ISO 9001 | Mosinee, WI | MillingWeldingGrinding | ISO 9001 |
| Sunset Industries Inc Milling, Turning, Swiss, Casting, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Mentor, OH | MillingTurningSwissCastingEDMGrindingFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Super Web Digital, Inc Milling, Turning, Welding, Grinding | West Babylon, NY | MillingTurningWeldingGrinding | - |