| San Diego Precision Machining Inc Milling, Turning, Welding, EDM · ISO 9001, AS9100 | San Diego, CA | MillingTurningWeldingEDM | ISO 9001, AS9100 |
| Santa Lucia Manufacturing, Inc Milling, Turning, Grinding | Atascadero, CA | MillingTurningGrinding | - |
| Sarco Precision, Inc Milling, Turning · ISO 9001, AS9100, ITAR | Mount Vernon, WA | MillingTurning | ISO 9001, AS9100, ITAR |
| Savage Machining Inc Milling, Turning, EDM, Finishing, Assembly · ISO 9001 | Simi Valley, CA | MillingTurningEDMFinishingAssembly | ISO 9001 |
| Schaefer Screw Products Co Milling, Turning, Grinding, Finishing | Garden City, MI | MillingTurningGrindingFinishing | - |
| Schmid Tool & Engineering Corp Milling, Turning, Swiss, Stamping, Grinding, Finishing, Assembly · ISO 9001, ITAR | Villa Park, IL | MillingTurningSwissStampingGrindingFinishingAssembly | ISO 9001, ITAR |
| Schred Machine Company, Inc Milling, Turning · AS9100 | Warminster, PA | MillingTurning | AS9100 |
| Scientific Tool Milling, Turning, Grinding | Syracuse, NY | MillingTurningGrinding | - |
| Seneca Manufacturing LLC Milling, Turning, Welding | Tiffin, OH | MillingTurningWelding | - |
| Sepco Erie Milling, Turning, Stamping · ISO 9001 | Erie, PA | MillingTurningStamping | ISO 9001 |
| Serrano Industries, Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001, AS9100 | Santa Fe Springs, CA | MillingTurningSwissEDMGrinding | ISO 9001, AS9100 |
| Seven Star Marine Inc Milling, Turning, Waterjet, Bending, Welding, Finishing · ISO 9001 | Newport, RI | MillingTurningWaterjetBendingWeldingFinishing | ISO 9001 |
| SFC Tec, Inc Milling, Turning, Laser, Bending, Welding | Delta, UT | MillingTurningLaserBendingWelding | - |
| Shamrock Machining Inc Milling, Turning, Bending, Laser, Welding · ISO 9001 | Spokane Valley, WA | MillingTurningBendingLaserWelding | ISO 9001 |
| Sharp Dimension Inc Milling, Turning, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001, ITAR | Fremont, CA | MillingTurningBendingWeldingGrindingFinishingAssembly | ISO 9001, ITAR |
| 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 |
| 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 |
| SKP Machine Enterprises LLC Milling, Turning | Monticello, KY | MillingTurning | - |
| Skytop Machine and Tool, Inc Milling, Turning, Waterjet, Welding, Grinding | Port Matilda, PA | MillingTurningWaterjetWeldingGrinding | - |
| Slim Haney Machining Inc Milling, Turning, Welding | Tulsa, OK | MillingTurningWelding | - |
| SLT Machine Works LLC Milling, Turning · ISO 9001, AS9100 | Stafford, TX | MillingTurning | ISO 9001, AS9100 |
| Smith Metal, LLC Milling, Turning, Swiss, Laser, Waterjet, Bending, Welding, EDM, Grinding, Finishing · ISO 9001 | Augusta, MI | MillingTurningSwissLaserWaterjetBendingWeldingEDMGrindingFinishing | ISO 9001 |
| SMT Machine & Tool Milling, Turning, Welding, Casting | Green Bay, WI | MillingTurningWeldingCasting | - |
| Snoe, Inc. Machining & Welding Milling, Turning, Welding · ISO 9001 | Caldwell, TX | MillingTurningWelding | ISO 9001 |
| Soflo Machining Milling, Turning, Laser, Waterjet, Welding, Grinding, Finishing · ISO 9001, AS9100 | Coral Springs, FL | MillingTurningLaserWaterjetWeldingGrindingFinishing | ISO 9001, AS9100 |
| Solvers Manufacturing Turning, Bending, Welding | Springfield, NE | TurningBendingWelding | - |
| Sonoma Industries Inc Milling, Turning, Swiss · ISO 9001, AS9100, ITAR | Bell Gardens, CA | MillingTurningSwiss | ISO 9001, AS9100, ITAR |
| Southeastern Machine Works, Inc Milling, Turning, Welding | Live Oak, FL | MillingTurningWelding | - |
| Southern Precision Machining Milling, Turning, Grinding, Finishing · ISO 9001, AS9100, ITAR | Shelbyville, TN | MillingTurningGrindingFinishing | ISO 9001, AS9100, ITAR |
| Southern Precision, Inc Milling, Turning, Stamping | Saint Rose, LA | MillingTurningStamping | - |
| 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 |
| 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 |
| Spartan Machine LLC Milling, Turning | Spring, TX | MillingTurning | - |
| Sparton Technology Corp Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100 | Hudson, NH | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100 |
| 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 Roller and Machine Inc Milling, Turning, Grinding | Berwick, PA | MillingTurningGrinding | - |
| 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 | - |
| Srpm Inc Milling, Turning, Assembly · ISO 9001, ITAR | Solon, OH | MillingTurningAssembly | ISO 9001, ITAR |
| SRS Fabrication Inc. Milling, Turning, Bending, Welding, Waterjet | North Las Vegas, NV | MillingTurningBendingWeldingWaterjet | - |
| Sse Steel Fabrication Milling, Turning, Bending, Welding | Saint Bernard, LA | MillingTurningBendingWelding | - |
| Stampede Die Corp Milling, Turning, Waterjet, Welding, Casting, EDM | Wayland, MI | MillingTurningWaterjetWeldingCastingEDM | - |
| Standard Locknut, LLC Milling, Turning | Westfield, IN | MillingTurning | - |
| Stanfordville Machine & Manufacturing Co Inc Milling, Turning, Swiss, Welding, EDM, Grinding · ISO 9001, AS9100 | Poughkeepsie, NY | MillingTurningSwissWeldingEDMGrinding | ISO 9001, AS9100 |
| Stanton Precision Products L.L.C Milling, Turning, Swiss, Grinding · CMMC | Butler, NJ | MillingTurningSwissGrinding | CMMC |