| Shamrock Precision Milling, Turning, Bending · ISO 9001, AS9100 | Dallas, TX | MillingTurningBending | ISO 9001, AS9100 |
| Sharp Tool Manufacturing Milling, Turning, Welding · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningWelding | ISO 9001, AS9100, ITAR, CMMC |
| Shaw Industries Co. LLC Milling, Turning, Welding, EDM · ISO 9001, ITAR | Franklin, PA | MillingTurningWeldingEDM | ISO 9001, ITAR |
| Sicom Industries USA LLC Milling, Turning, Waterjet · ISO 9001, AS9100, CMMC | Stanwood, WA | MillingTurningWaterjet | ISO 9001, AS9100, CMMC |
| Sifco Industries Inc Forging, Finishing, Assembly · ISO 9001, NADCAP | Cleveland, OH | ForgingFinishingAssembly | ISO 9001, NADCAP |
| Skillcraft Machine Tool Co Inc Milling, Turning, Welding | South Windsor, CT | MillingTurningWelding | - |
| SLT Machine Works LLC Milling, Turning · ISO 9001, AS9100 | Stafford, TX | MillingTurning | ISO 9001, AS9100 |
| Smith Brothers Tool Company Milling, Welding · ISO 9001, AS9100, ITAR | Shelby Township, MI | MillingWelding | ISO 9001, AS9100, ITAR |
| Snider Precision, Inc Milling · ISO 9001, AS9100 | San Luis Obispo, CA | Milling | ISO 9001, AS9100 |
| Solidiform, Inc Milling, Casting, Finishing | Fort Worth, TX | MillingCastingFinishing | - |
| Sonoma Industries Inc Milling, Turning, Swiss · ISO 9001, AS9100, ITAR | Bell Gardens, CA | MillingTurningSwiss | ISO 9001, AS9100, ITAR |
| Southern Precision Machining Milling, Turning, Grinding, Finishing · ISO 9001, AS9100, ITAR | Shelbyville, TN | MillingTurningGrindingFinishing | ISO 9001, AS9100, ITAR |
| 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 |
| Srpm Inc Milling, Turning, Assembly · ISO 9001, ITAR | Solon, OH | MillingTurningAssembly | ISO 9001, ITAR |
| 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 |
| Statt Engineering LLC Milling, Stamping · AS9100, ITAR | Martinsville, IN | MillingStamping | AS9100, ITAR |
| Steadfast Machine Milling, Turning · AS9100, ITAR | Bixby, OK | MillingTurning | AS9100, ITAR |
| Steelhead Composites, Inc Welding · ISO 9001, AS9100 | Golden, CO | Welding | ISO 9001, AS9100 |
| Steelhead Metal Corp Milling, Turning, Laser, Waterjet, Bending, EDM, Finishing · ISO 9001 | Nampa, ID | MillingTurningLaserWaterjetBendingEDMFinishing | ISO 9001 |
| Stellar Precision Components. Ltd Milling, Turning, EDM, Grinding · ISO 9001, AS9100 | Jeannette, PA | MillingTurningEDMGrinding | ISO 9001, AS9100 |
| Stork Precision Machining LLC Milling, Turning, Welding, EDM, Grinding · ISO 9001, CMMC | Washington, MO | MillingTurningWeldingEDMGrinding | ISO 9001, CMMC |
| Straton Industries Inc Milling, Turning, Stamping, EDM, Grinding, Finishing, Assembly · AS9100, ITAR, CMMC | Stratford, CT | MillingTurningStampingEDMGrindingFinishingAssembly | AS9100, ITAR, CMMC |
| Striking Precision Welding & Fabrication Milling, Bending, Welding · ISO 9001, ITAR | Cedar Park, TX | MillingBendingWelding | ISO 9001, ITAR |
| 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 |
| Sunnycor Inc Milling, Turning, Grinding, Assembly · AS9100, ITAR | Torrington, CT | MillingTurningGrindingAssembly | AS9100, ITAR |
| Suntiger Industries LLC Welding · ISO 9001, AS9100, ITAR | Oceanside, CA | Welding | ISO 9001, AS9100, ITAR |
| Superior Jig Inc Milling, EDM · ISO 9001, ITAR | Anaheim, CA | MillingEDM | ISO 9001, ITAR |
| Superior Machining and Fabrication Inc Milling, Turning, Grinding, Assembly · ISO 9001, AS9100, ITAR | Muenster, TX | MillingTurningGrindingAssembly | ISO 9001, AS9100, ITAR |
| Superior Metal Products Inc Milling, Turning, Grinding · ISO 9001 | Louviers, CO | MillingTurningGrinding | ISO 9001 |
| Superior Thread Rolling Co, LLC Milling, Turning, Grinding · ISO 9001, AS9100, NADCAP | Arleta, CA | MillingTurningGrinding | ISO 9001, AS9100, NADCAP |
| Swiss Wire EDM Milling, Turning, Welding, EDM · ISO 9001, ITAR, NADCAP | Costa Mesa, CA | MillingTurningWeldingEDM | ISO 9001, ITAR, NADCAP |
| Szabo Precision Milling, Turning · ISO 9001, AS9100 | Diamond Springs, CA | MillingTurning | ISO 9001, AS9100 |
| T.e.t. Mfg. Co Inc Milling, Grinding, Finishing | Middlefield, CT | MillingGrindingFinishing | - |
| T.P. Engineering Inc Milling, Turning, Swiss, Welding, Grinding, Assembly · ISO 9001, ITAR, ISO 13485 | Danbury, CT | MillingTurningSwissWeldingGrindingAssembly | ISO 9001, ITAR, ISO 13485 |
| Tam Metal Products Punching, Welding, Stamping, Finishing · NADCAP | Mahwah, NJ | PunchingWeldingStampingFinishing | NADCAP |
| Tampa Bay Machining Milling, Turning, Welding, EDM · ISO 9001, AS9100, ITAR | Tampa, FL | MillingTurningWeldingEDM | ISO 9001, AS9100, ITAR |
| TBT Machining Milling | Fremont, CA | Milling | - |
| Tech Heavy Industries, Inc Milling, Waterjet, Bending, Welding | Riverside, WA | MillingWaterjetBendingWelding | - |
| Techcraft Precision Milling, Finishing · AS9100, ITAR, CMMC | Bellingham, WA | MillingFinishing | AS9100, ITAR, CMMC |
| Temco Precision Machining Milling, EDM · ISO 9001, AS9100 | Manchester, NH | MillingEDM | ISO 9001, AS9100 |
| The Progress Group, Inc Turning, Welding, Assembly · ISO 9001 | Schererville, IN | TurningWeldingAssembly | ISO 9001 |
| Thermo-Craft Engineering Corp Milling, Turning, Waterjet, Punching, Bending, Welding, Grinding, Assembly | Lynn, MA | MillingTurningWaterjetPunchingBendingWeldingGrindingAssembly | - |
| Third Reef Machining and Engineering Ltd. Co Milling, Bending, Welding, Finishing | Cottonwood Heights, UT | MillingBendingWeldingFinishing | - |
| Thrust Tech, Inc Turning, Welding | Miami, FL | TurningWelding | - |
| Timber Mountain Precision Inc Milling · ISO 9001, AS9100 | Queen Creek, AZ | Milling | ISO 9001, AS9100 |
| Tin-Mar, Inc Milling, Turning, Waterjet, Welding, EDM · ISO 9001, AS9100 | Huntsville, AL | MillingTurningWaterjetWeldingEDM | ISO 9001, AS9100 |
| TMD Machining Inc Milling, Turning, Swiss, EDM, Grinding · AS9100, NADCAP | Plainwell, MI | MillingTurningSwissEDMGrinding | AS9100, NADCAP |