| Shieldcoat Technologies Inc Finishing, Assembly · ISO 9001, ITAR | Lufkin, TX | FinishingAssembly | ISO 9001, ITAR |
| Sifco Industries Inc Forging, Finishing, Assembly · ISO 9001, NADCAP | Cleveland, OH | ForgingFinishingAssembly | ISO 9001, NADCAP |
| Sinclair and Sons Custom Welding and Machining Service Inc Milling, Turning, Waterjet, Welding, Assembly · ISO 9001, AS9100, NADCAP | Wichita, KS | MillingTurningWaterjetWeldingAssembly | ISO 9001, AS9100, NADCAP |
| Sintel Inc Laser, Punching, Bending, Welding, Finishing, Assembly | Spring Lake, MI | LaserPunchingBendingWeldingFinishingAssembly | - |
| Sirois Tool Company, Inc Milling, Turning, EDM, Grinding, Assembly | Berlin, CT | MillingTurningEDMGrindingAssembly | - |
| Sonic Aerospace Inc Milling, Turning, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Chandler, AZ | MillingTurningGrindingFinishingAssembly | ISO 9001, AS9100 |
| Sonic Manufacturing Corporation Milling, Welding, EDM, Grinding, Finishing, Assembly · AS9100, NADCAP | Elk Grove Village, IL | MillingWeldingEDMGrindingFinishingAssembly | AS9100, NADCAP |
| Sound Manufacturing, Inc Milling, Laser, Punching, Bending, Welding, Assembly · ISO 9001 | Old Saybrook, CT | MillingLaserPunchingBendingWeldingAssembly | ISO 9001 |
| Southwest Industrial Sales LLC Milling, Turning, Swiss, Bending, Welding, EDM, Assembly · ISO 9001, AS9100, ITAR, ISO 13485, CMMC | Chandler, AZ | MillingTurningSwissBendingWeldingEDMAssembly | ISO 9001, AS9100, ITAR, ISO 13485, CMMC |
| Sparton Technology Corp Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100 | Hudson, NH | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100 |
| Specialty Engineering Inc Laser, Punching, Bending, Welding, Assembly · ISO 9001 | Saint Paul, MN | LaserPunchingBendingWeldingAssembly | ISO 9001 |
| Specialty Machine Milling, Turning, Swiss, Laser, Bending, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Lago Vista, TX | MillingTurningSwissLaserBendingWeldingEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| Specialty Machining Inc Milling, Turning, Welding, Assembly · ISO 9001, ISO 13485 | Newberry, FL | MillingTurningWeldingAssembly | ISO 9001, ISO 13485 |
| 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 |
| SpecWeld Milling, Welding, Assembly · ISO 9001 | Lake Orion, MI | MillingWeldingAssembly | ISO 9001 |
| SPM Milling, Turning, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Portland, OR | MillingTurningWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Springfield Tool and Die Milling, Turning, Grinding, Assembly | Duncan, SC | MillingTurningGrindingAssembly | - |
| Square Deal Machining Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly | Marathon, NY | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | - |
| Srpm Inc Milling, Turning, Assembly · ISO 9001, ITAR | Solon, OH | MillingTurningAssembly | ISO 9001, ITAR |
| Stanley Spring and Stamping Corp Laser, Bending, Stamping, Assembly | Chicago, IL | LaserBendingStampingAssembly | - |
| Steelcrest Precision, Inc Milling, Turning, Swiss, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100 | Wauseon, OH | MillingTurningSwissWeldingEDMGrindingAssembly | ISO 9001, AS9100 |
| Stephens Precision, Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Bradford, VT | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| Stever Locke, Inc Turning, Stamping, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR | Honeoye Falls, NY | TurningStampingGrindingFinishingAssembly | ISO 9001, AS9100, ITAR |
| Steward Machine Co., Inc Turning, Welding, Assembly | Birmingham, AL | TurningWeldingAssembly | - |
| Stigtec Manufacturing Milling, Welding, EDM, Grinding, Finishing, Assembly | San Marcos, CA | MillingWeldingEDMGrindingFinishingAssembly | - |
| Stockton Tri-Industries, LLC Milling, Turning, Waterjet, Bending, Welding, Assembly | Stockton, CA | MillingTurningWaterjetBendingWeldingAssembly | - |
| Straton Industries Inc Milling, Turning, Stamping, EDM, Grinding, Finishing, Assembly · AS9100, ITAR, CMMC | Stratford, CT | MillingTurningStampingEDMGrindingFinishingAssembly | AS9100, ITAR, CMMC |
| Strickland Industries Milling, Turning, Laser, Bending, Welding, Assembly | Mansfield, TX | MillingTurningLaserBendingWeldingAssembly | - |
| Strickland Machine Co LLC Milling, Turning, Welding, Stamping, Grinding, Finishing, Assembly | North Chesterfield, VA | MillingTurningWeldingStampingGrindingFinishingAssembly | - |
| Strohwig Industries, Inc Milling, Turning, Casting, EDM, Grinding, Finishing, Assembly · ISO 9001, ITAR, CMMC | Richfield, WI | MillingTurningCastingEDMGrindingFinishingAssembly | ISO 9001, ITAR, CMMC |
| Strom Manufacturing, LLC Milling, Turning, Finishing, Assembly · ISO 9001 | North Plains, OR | MillingTurningFinishingAssembly | ISO 9001 |
| Sugar River Machine Inc Milling, Turning, Welding, Grinding, Finishing, Assembly | South Beloit, IL | MillingTurningWeldingGrindingFinishingAssembly | - |
| Sunnycor Inc Milling, Turning, Grinding, Assembly · AS9100, ITAR | Torrington, CT | MillingTurningGrindingAssembly | AS9100, ITAR |
| Sunset Industries Inc Milling, Turning, Swiss, Casting, EDM, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Mentor, OH | MillingTurningSwissCastingEDMGrindingFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Superior Machining and Fabrication Inc Milling, Turning, Grinding, Assembly · ISO 9001, AS9100, ITAR | Muenster, TX | MillingTurningGrindingAssembly | ISO 9001, AS9100, ITAR |
| Superior Technology Inc Milling, Turning, Swiss, Welding, Grinding, Finishing, Assembly · ISO 9001 | Rochester, NY | MillingTurningSwissWeldingGrindingFinishingAssembly | ISO 9001 |
| Support Equipment Inc Milling, Turning, Welding, EDM, Finishing, Assembly · ISO 9001, AS9100, ITAR | Escondido, CA | MillingTurningWeldingEDMFinishingAssembly | ISO 9001, AS9100, ITAR |
| Swanton Welding & Machining Co Inc Milling, Laser, Bending, Welding, Finishing, Assembly | Swanton, OH | MillingLaserBendingWeldingFinishingAssembly | - |
| Swift Industries Inc Milling, Laser, Punching, Bending, Welding, Stamping, Grinding, Finishing, Assembly · ISO 9001 | Suwanee, GA | MillingLaserPunchingBendingWeldingStampingGrindingFinishingAssembly | ISO 9001 |
| Swiss Productions, Inc Milling, Turning, Assembly · ISO 9001 | Liberty Lake, WA | MillingTurningAssembly | ISO 9001 |
| Swiss Screw Products Inc Milling, Turning, Swiss, Grinding, Assembly · ISO 9001 | Santa Clara, CA | MillingTurningSwissGrindingAssembly | ISO 9001 |
| Synergy Manufacturing Services LLC Welding, Assembly | Grafton, WI | WeldingAssembly | - |
| Systems Powered Manufacturing, LLC Grinding, Finishing, Assembly | Saint Charles, IL | GrindingFinishingAssembly | - |
| T.P. Engineering Inc Milling, Turning, Swiss, Welding, Grinding, Assembly · ISO 9001, ITAR, ISO 13485 | Danbury, CT | MillingTurningSwissWeldingGrindingAssembly | ISO 9001, ITAR, ISO 13485 |
| Tabet Manufacturing Co Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Norfolk, VA | MillingTurningLaserWaterjetPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Talladega Castings & Machine Co Welding, Assembly · ISO 9001 | Talladega, AL | WeldingAssembly | ISO 9001 |
| Tampa Brass and Aluminum Corporation Milling, Turning, Welding, Casting, Assembly | Tampa, FL | MillingTurningWeldingCastingAssembly | - |
| Team Technologies Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100 | Albuquerque, NM | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, AS9100 |
| Tec Inc Milling, Turning, Swiss, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Frederick, MD | MillingTurningSwissLaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |