| 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 |
| Silver Creek Machine Ltd Milling, Turning, Bending, Finishing · ISO 9001 | Fort Worth, TX | MillingTurningBendingFinishing | ISO 9001 |
| Sintel Inc Laser, Punching, Bending, Welding, Finishing, Assembly | Spring Lake, MI | LaserPunchingBendingWeldingFinishingAssembly | - |
| SJD Machining, Inc Milling, Turning, EDM, Grinding, Finishing | Meadville, PA | MillingTurningEDMGrindingFinishing | - |
| SJK Machine LLC Milling, Turning, Waterjet, Welding, EDM, Finishing | Minerva, OH | MillingTurningWaterjetWeldingEDMFinishing | - |
| Smith Metal, LLC Milling, Turning, Swiss, Laser, Waterjet, Bending, Welding, EDM, Grinding, Finishing · ISO 9001 | Augusta, MI | MillingTurningSwissLaserWaterjetBendingWeldingEDMGrindingFinishing | ISO 9001 |
| Soflo Machining Milling, Turning, Laser, Waterjet, Welding, Grinding, Finishing · ISO 9001, AS9100 | Coral Springs, FL | MillingTurningLaserWaterjetWeldingGrindingFinishing | ISO 9001, AS9100 |
| Solidiform, Inc Milling, Casting, Finishing | Fort Worth, TX | MillingCastingFinishing | - |
| 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 |
| Southern Ohio Manufacturing Milling, Turning, Laser, Bending, Welding, Grinding, Finishing | Amelia, OH | MillingTurningLaserBendingWeldingGrindingFinishing | - |
| SP Manufacturing Inc Milling, Turning, Welding, Finishing · ISO 9001, AS9100 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100 |
| Sparton Technology Corp Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100 | Hudson, NH | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100 |
| Spectrum Custom Molds & Manufacturing, Inc Milling, Turning, Laser, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Palmetto, FL | MillingTurningLaserWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Speed Fabrication LLC Laser, Bending, Welding, Finishing | Perryville, MO | LaserBendingWeldingFinishing | - |
| SPM Milling, Turning, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Portland, OR | MillingTurningWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Spring Creek Machining, Inc Milling, Turning, Waterjet, Bending, Welding, EDM, Grinding, Finishing | Lowell, AR | MillingTurningWaterjetBendingWeldingEDMGrindingFinishing | - |
| Spsm Industries Inc Welding, Finishing | Burnsville, MN | WeldingFinishing | - |
| Square Deal Machining Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly | Marathon, NY | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | - |
| Square One Coating Systems LLC Finishing · NADCAP | Oriskany, NY | Finishing | NADCAP |
| ST Paul Brass Foundry Co Casting, Finishing · ISO 9001, AS9100, ITAR, CMMC | Saint Paul, MN | CastingFinishing | ISO 9001, AS9100, ITAR, CMMC |
| Standard Machine, LLC Milling, Turning, Welding, Casting, Grinding, Finishing | Cleveland, OH | MillingTurningWeldingCastingGrindingFinishing | - |
| Steelhead Metal Corp Milling, Turning, Laser, Waterjet, Bending, EDM, Finishing · ISO 9001 | Nampa, ID | MillingTurningLaserWaterjetBendingEDMFinishing | ISO 9001 |
| Stellar Industries LLC Laser, Bending, Welding, Stamping, Finishing · ISO 9001 | Nappanee, IN | LaserBendingWeldingStampingFinishing | ISO 9001 |
| Stever Locke, Inc Turning, Stamping, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR | Honeoye Falls, NY | TurningStampingGrindingFinishingAssembly | ISO 9001, AS9100, ITAR |
| Stigtec Manufacturing Milling, Welding, EDM, Grinding, Finishing, Assembly | San Marcos, CA | MillingWeldingEDMGrindingFinishingAssembly | - |
| Stone Machine Co. Inc Milling, Turning, Grinding, Finishing | Chester, NH | MillingTurningGrindingFinishing | - |
| Straitek, LLC Milling, Bending, Finishing · ITAR, ISO 13485 | Danbury, CT | MillingBendingFinishing | ITAR, ISO 13485 |
| Strickland Machine Co LLC Milling, Turning, Welding, Stamping, Grinding, Finishing, Assembly | North Chesterfield, VA | MillingTurningWeldingStampingGrindingFinishingAssembly | - |
| Strom Manufacturing, LLC Milling, Turning, Finishing, Assembly · ISO 9001 | North Plains, OR | MillingTurningFinishingAssembly | ISO 9001 |
| Strong Forge & Fabrication, LLC Milling, Bending, Welding, Finishing | Batavia, NY | MillingBendingWeldingFinishing | - |
| Stuecklen Manufacturing Co Bending, Finishing | Franklin Park, IL | BendingFinishing | - |
| Subtract LLC Milling, Turning, Swiss, Laser, Waterjet, Welding, EDM, Finishing | Muncie, IN | MillingTurningSwissLaserWaterjetWeldingEDMFinishing | - |
| Sugar River Machine Inc Milling, Turning, Welding, Grinding, Finishing, Assembly | South Beloit, IL | MillingTurningWeldingGrindingFinishingAssembly | - |
| Sullivan Precision Metal Finishing Finishing · AS9100, ITAR | Sullivan, MO | Finishing | AS9100, ITAR |
| Summit Machining Co., Ltd Milling, Turning, Welding, Stamping, Casting, Finishing | Mogadore, OH | MillingTurningWeldingStampingCastingFinishing | - |
| Summit Products Inc Milling, Bending, Welding, Finishing | Altoona, IA | MillingBendingWeldingFinishing | - |
| 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 Grinding Corp Milling, Turning, Grinding, Finishing | Antigo, WI | MillingTurningGrindingFinishing | - |
| 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 |
| SX Industries, Inc Casting, Finishing | Stoughton, MA | CastingFinishing | - |
| Sycamore Precision, Inc Milling, Casting, Finishing | Genoa, IL | MillingCastingFinishing | - |
| T & D Specialties Milling, Turning, Swiss, Welding, Finishing · ISO 9001 | Oxford, MA | MillingTurningSwissWeldingFinishing | ISO 9001 |
| T & T Metals Milling, Laser, Punching, Bending, Welding, Finishing · ISO 9001 | Covina, CA | MillingLaserPunchingBendingWeldingFinishing | ISO 9001 |
| T.e.t. Mfg. Co Inc Milling, Grinding, Finishing | Middlefield, CT | MillingGrindingFinishing | - |
| T.R. Reed Enterprises Inc Milling, Turning, Finishing · ISO 9001, AS9100 | Ponder, TX | MillingTurningFinishing | ISO 9001, AS9100 |
| Tabet Manufacturing Co Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Norfolk, VA | MillingTurningLaserWaterjetPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Team Engineering Inc Laser, Waterjet, Finishing · ISO 9001 | Mesa, AZ | LaserWaterjetFinishing | ISO 9001 |