| Relentless Machine Milling, Turning, EDM | Roy, UT | MillingTurningEDM | - |
| Rentiel Precision Laser Cutting L.L.C Milling, Laser, Welding | Tacoma, WA | MillingLaserWelding | - |
| Rig Machine Works LLC Milling, Turning, Bending, Welding, Grinding | Stevensville, MT | MillingTurningBendingWeldingGrinding | - |
| S & R Tool, Inc Milling, Turning, Welding, EDM · AS9100 | Lakeville, NY | MillingTurningWeldingEDM | AS9100 |
| S R Machining, Inc Milling, Turning, Swiss, Welding, Casting · ISO 9001, AS9100 | Norco, CA | MillingTurningSwissWeldingCasting | ISO 9001, AS9100 |
| Saar Corp Milling, Turning, Swiss, Finishing, Assembly · AS9100 | Farmington, CT | MillingTurningSwissFinishingAssembly | AS9100 |
| Sabrin Turning, Welding, EDM, Assembly · AS9100 | Pasadena, CA | TurningWeldingEDMAssembly | AS9100 |
| Salco Inc Milling, Turning, Swiss, Welding, Assembly · ISO 9001 | Arvada, CO | MillingTurningSwissWeldingAssembly | ISO 9001 |
| 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 |
| Seaberg Industries Turning, Bending, Laser, Welding · ISO 9001 | Davenport, IA | TurningBendingLaserWelding | ISO 9001 |
| Sepco Erie Milling, Turning, Stamping · ISO 9001 | Erie, PA | MillingTurningStamping | ISO 9001 |
| Shapes Precision Manufacturing Milling, Welding · ISO 9001, AS9100, NADCAP | Palm Bay, FL | MillingWelding | ISO 9001, AS9100, NADCAP |
| Sharp Dimension Inc Milling, Turning, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001, ITAR | Fremont, CA | MillingTurningBendingWeldingGrindingFinishingAssembly | ISO 9001, ITAR |
| Shaw Industries Co. LLC Milling, Turning, Welding, EDM · ISO 9001, ITAR | Franklin, PA | MillingTurningWeldingEDM | ISO 9001, ITAR |
| Siddhi Integrated Manufacturing Services Inc Milling, Turning, Swiss, Stamping, EDM · ISO 9001, ITAR | Clarksville, IN | MillingTurningSwissStampingEDM | 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 |
| Smith Metal, LLC Milling, Turning, Swiss, Laser, Waterjet, Bending, Welding, EDM, Grinding, Finishing · ISO 9001 | Augusta, MI | MillingTurningSwissLaserWaterjetBendingWeldingEDMGrindingFinishing | ISO 9001 |
| SMS Precision Tech, LLC Waterjet, Welding, EDM · ISO 9001 | Tomball, TX | WaterjetWeldingEDM | ISO 9001 |
| Snowline Engineering Laser, Waterjet, Welding, Finishing · ISO 9001, AS9100, NADCAP | Cameron Park, CA | LaserWaterjetWeldingFinishing | ISO 9001, AS9100, NADCAP |
| Sonic Aerospace Inc Milling, Turning, Grinding, Finishing, Assembly · ISO 9001, AS9100 | Chandler, AZ | MillingTurningGrindingFinishingAssembly | ISO 9001, AS9100 |
| Sonoma Industries Inc Milling, Turning, Swiss · ISO 9001, AS9100, ITAR | Bell Gardens, CA | MillingTurningSwiss | ISO 9001, AS9100, ITAR |
| South Bend Form Tool Co Milling, Turning, EDM | South Bend, IN | MillingTurningEDM | - |
| SP Manufacturing Inc Milling, Turning, Welding, Finishing · ISO 9001, AS9100 | Livermore, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100 |
| Specialty Machining Inc Milling, Turning, Welding, Assembly · ISO 9001, ISO 13485 | Newberry, FL | MillingTurningWeldingAssembly | ISO 9001, ISO 13485 |
| Spectrum Custom Molds & Manufacturing, Inc Milling, Turning, Laser, Welding, EDM, Grinding, Finishing, Assembly · ISO 9001 | Palmetto, FL | MillingTurningLaserWeldingEDMGrindingFinishingAssembly | ISO 9001 |
| Springs Fabrication, LLC Bending, Welding, Waterjet · ISO 9001, ITAR | Colorado Springs, CO | BendingWeldingWaterjet | ISO 9001, ITAR |
| Spuncast Inc Casting · ISO 9001 | Watertown, WI | Casting | ISO 9001 |
| Stampings of Minnesota Inc Laser, Bending, Stamping · ISO 9001, AS9100 | Lakeville, MN | LaserBendingStamping | ISO 9001, AS9100 |
| 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 |
| Stentech, Inc Milling, Turning, Laser, EDM · ISO 9001, AS9100, ITAR | Lumberton Township, NJ | MillingTurningLaserEDM | ISO 9001, AS9100, ITAR |
| Stever Locke, Inc Turning, Stamping, Grinding, Finishing, Assembly · ISO 9001, AS9100, ITAR | Honeoye Falls, NY | TurningStampingGrindingFinishingAssembly | ISO 9001, AS9100, ITAR |
| Straitek, LLC Milling, Bending, Finishing · ITAR, ISO 13485 | Danbury, CT | MillingBendingFinishing | ITAR, ISO 13485 |
| Streamline Machine Source Inc Milling, Laser, Waterjet, Grinding · ISO 9001 | Greenville, MI | MillingLaserWaterjetGrinding | ISO 9001 |
| Strom Manufacturing, LLC Milling, Turning, Finishing, Assembly · ISO 9001 | North Plains, OR | MillingTurningFinishingAssembly | ISO 9001 |
| Sturdy Grinding & Machining Inc Grinding, Finishing · ISO 9001 | New Haven, MI | GrindingFinishing | 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 |
| Suntiger Industries LLC Welding · ISO 9001, AS9100, ITAR | Oceanside, CA | Welding | ISO 9001, AS9100, ITAR |
| Superior Machine & Tool Milling, Turning, Welding · ISO 9001 | Fort Wayne, IN | MillingTurningWelding | 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 |
| Swiss Productions, Inc Milling, Turning, Assembly · ISO 9001 | Liberty Lake, WA | MillingTurningAssembly | ISO 9001 |
| Swiss Wire EDM Milling, Turning, Welding, EDM · ISO 9001, ITAR, NADCAP | Costa Mesa, CA | MillingTurningWeldingEDM | ISO 9001, ITAR, NADCAP |
| Swissturn/usa, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR, CMMC | Oxford, MA | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR, CMMC |
| Target Marketing Associates, Inc Welding | Sturgeon Bay, WI | Welding | - |
| Tassell CNC Milling, Turning | Nunica, MI | MillingTurning | - |
| Tecton Industries Inc Milling, Turning, Casting, Grinding · ISO 9001, AS9100 | Spencer, IA | MillingTurningCastingGrinding | ISO 9001, AS9100 |
| Tiger Industrial Inc Milling, Turning, Laser | Spicewood, TX | MillingTurningLaser | - |