| Service Metal Fabricators Inc Milling, Punching, Bending, Welding, Stamping, Grinding, Finishing, Assembly | Williamsburg, VA | MillingPunchingBendingWeldingStampingGrindingFinishingAssembly | - |
| Seven Star Marine Inc Milling, Turning, Waterjet, Bending, Welding, Finishing · ISO 9001 | Newport, RI | MillingTurningWaterjetBendingWeldingFinishing | ISO 9001 |
| Shamong Manufacturing Laser, Punching, Bending, Welding, Stamping, Grinding, Finishing, Assembly · AS9100, NADCAP | Shamong, NJ | LaserPunchingBendingWeldingStampingGrindingFinishingAssembly | AS9100, NADCAP |
| Shape Shifters Inc Milling, Waterjet, Bending, Welding, Stamping, Finishing | Bloomfield, IN | MillingWaterjetBendingWeldingStampingFinishing | - |
| Sharp Dimension Inc Milling, Turning, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001, ITAR | Fremont, CA | MillingTurningBendingWeldingGrindingFinishingAssembly | ISO 9001, ITAR |
| Sheet Metal Solutions Inc Welding, Finishing | Tangent, OR | WeldingFinishing | - |
| Sifco Industries Inc Forging, Finishing, Assembly · ISO 9001, NADCAP | Cleveland, OH | ForgingFinishingAssembly | ISO 9001, NADCAP |
| Silicon Valley Precision Inc Milling, Turning, Welding, Casting, Grinding, Finishing · ITAR | Livermore, CA | MillingTurningWeldingCastingGrindingFinishing | ITAR |
| Silver Creek Machine Ltd Milling, Turning, Bending, Finishing · ISO 9001 | Fort Worth, TX | MillingTurningBendingFinishing | ISO 9001 |
| Slagel Manufacturing, Inc Bending, Welding, Finishing · ISO 9001 | Forrest, IL | BendingWeldingFinishing | ISO 9001 |
| 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 |
| Southern Precision Machining Milling, Turning, Grinding, Finishing · ISO 9001, AS9100, ITAR | Shelbyville, TN | MillingTurningGrindingFinishing | ISO 9001, AS9100, ITAR |
| Southwest Precision Machining, L.L.C Milling, Turning, Swiss, Welding, Finishing | Tucson, AZ | MillingTurningSwissWeldingFinishing | - |
| 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 |
| 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 | - |
| 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 & Manufacturing, LLC Finishing · ITAR | Greenville, KY | Finishing | ITAR |
| Starn Tool & Manufacturing Company Milling, Turning, EDM, Grinding, Finishing · ISO 9001, ITAR | Meadville, PA | MillingTurningEDMGrindingFinishing | ISO 9001, ITAR |
| 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 | - |
| Straitek, LLC Milling, Bending, Finishing · ITAR, ISO 13485 | Danbury, CT | MillingBendingFinishing | ITAR, ISO 13485 |
| Straton Industries Inc Milling, Turning, Stamping, EDM, Grinding, Finishing, Assembly · AS9100, ITAR, CMMC | Stratford, CT | MillingTurningStampingEDMGrindingFinishingAssembly | AS9100, ITAR, CMMC |
| 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 | - |
| Sturdy Grinding & Machining Inc Grinding, Finishing · ISO 9001 | New Haven, MI | GrindingFinishing | ISO 9001 |
| Summit Machine Company Milling, Turning, Welding, Finishing · ISO 9001 | Alverton, PA | MillingTurningWeldingFinishing | ISO 9001 |
| 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 Steel Fabrication Welding, Finishing · ISO 9001, AS9100 | Eugene, OR | WeldingFinishing | ISO 9001, AS9100 |
| 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 Automation, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR, ISO 13485 | Barrington, IL | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR, ISO 13485 |
| Swiss Labs Machine and Engineering, Inc Milling, Turning, Swiss, Finishing · ISO 9001 | Franklin, IN | MillingTurningSwissFinishing | ISO 9001 |
| Swissturn/usa, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR, CMMC | Oxford, MA | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR, CMMC |
| T & D Specialties Milling, Turning, Swiss, Welding, Finishing · ISO 9001 | Oxford, MA | MillingTurningSwissWeldingFinishing | ISO 9001 |
| Tabet Manufacturing Co Inc Milling, Turning, Laser, Waterjet, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, ITAR | Norfolk, VA | MillingTurningLaserWaterjetPunchingBendingWeldingFinishingAssembly | ISO 9001, ITAR |
| Tag Team Manufacturing Turning, Welding, Finishing · ISO 9001 | Parker, CO | TurningWeldingFinishing | ISO 9001 |
| Tahl Inc Milling, Turning, Welding, EDM, Grinding, Finishing · ISO 9001, ITAR, CMMC | Tucson, AZ | MillingTurningWeldingEDMGrindingFinishing | ISO 9001, ITAR, CMMC |
| Tam Metal Products Punching, Welding, Stamping, Finishing · NADCAP | Mahwah, NJ | PunchingWeldingStampingFinishing | NADCAP |