| Roemer Machine Milling, Welding | Davenport, IA | MillingWelding | - |
| Rosado Welding Inc. Welding | Dallas, TX | Welding | - |
| Rose Metal Products Inc. Bending, Laser, Welding, Stamping | Springfield, MO | BendingLaserWeldingStamping | - |
| Ross Metal Works Welding | Houston, TX | Welding | - |
| S & S Machine Milling, Turning, Bending, Welding, Waterjet, EDM | Amherst, NH | MillingTurningBendingWeldingWaterjetEDM | - |
| Sadler Machine Co Inc Welding · ISO 9001 | Cedar Rapids, IA | Welding | ISO 9001 |
| Sanders Metal Products Inc Milling, Turning, Bending, Welding | Fargo, ND | MillingTurningBendingWelding | - |
| Scherer Metals - 1299 E. 58th Avenue, Denver Bending, Welding | Denver, CO | BendingWelding | - |
| Scientific Machine & Welding, Inc. Welding | Austin, TX | Welding | - |
| Seaberg Industries Turning, Bending, Laser, Welding · ISO 9001 | Davenport, IA | TurningBendingLaserWelding | ISO 9001 |
| Seal Tex Welding | Dallas, TX | Welding | - |
| Seattle Makers Laser, Welding, Metal AM | Seattle, WA | LaserWeldingMetal AM | - |
| SendCutSend Milling, Bending, Laser, Welding, Waterjet | Reno, NV | MillingBendingLaserWeldingWaterjet | - |
| Service Steel, Inc. Welding | Huntsville, AL | Welding | - |
| Shamrock Machining Inc Milling, Turning, Bending, Laser, Welding · ISO 9001 | Spokane Valley, WA | MillingTurningBendingLaserWelding | ISO 9001 |
| Sharp Tool Manufacturing Milling, Turning, Welding · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningWelding | ISO 9001, AS9100, ITAR, CMMC |
| Sharp Tooling Company Milling, Turning, Bending, Welding, Waterjet, EDM, Stamping, Metal AM | Buffalo, NY | MillingTurningBendingWeldingWaterjetEDMStampingMetal AM | - |
| Sheet Metal Specialists (SMS Fabrications, Inc.) Bending, Laser, Welding, Waterjet · ISO 9001 | Riverside, CA | BendingLaserWeldingWaterjet | ISO 9001 |
| Sick Fab LLC Milling, Bending, Welding | Las Vegas, NV | MillingBendingWelding | - |
| Slim Haney Machining Inc Milling, Turning, Welding | Tulsa, OK | MillingTurningWelding | - |
| SMT Machine & Tool Milling, Turning, Welding, Casting | Green Bay, WI | MillingTurningWeldingCasting | - |
| Snyder Industries Inc Milling, Turning, Welding · ISO 9001 | Tonawanda, NY | MillingTurningWelding | ISO 9001 |
| Solvers Manufacturing Turning, Bending, Welding | Springfield, NE | TurningBendingWelding | - |
| SOS Steel Co Inc Welding | Santa Clara, CA | Welding | - |
| South Austin Metals Bending, Welding | Austin, TX | BendingWelding | - |
| South Eastern Machining Inc Milling, Turning, Bending, Welding · ISO 9001 | Pelzer, SC | MillingTurningBendingWelding | ISO 9001 |
| Southeastern Machining Milling, Turning, Welding · ISO 9001 | Worthington, OH | MillingTurningWelding | ISO 9001 |
| Space Cadet CNC Routing Welding | Reno, NV | Welding | - |
| Specialty Metal Fabricators Bending, Welding | Portland, OR | BendingWelding | - |
| Spokane Metals Welding | Spokane Valley, WA | Welding | - |
| Spokane Tin & Sheet Iron Works, Inc. Bending, Welding | Spokane, WA | BendingWelding | - |
| Spring Grove Sheet Metal Bending, Laser, Welding | Cincinnati, OH | BendingLaserWelding | - |
| Springs Fabrication, LLC Bending, Welding, Waterjet · ISO 9001, ITAR | Colorado Springs, CO | BendingWeldingWaterjet | ISO 9001, ITAR |
| SRS Fabrication Inc. Milling, Turning, Bending, Welding, Waterjet | North Las Vegas, NV | MillingTurningBendingWeldingWaterjet | - |
| Steel Creations & Fabrication, Inc. Welding | Glendale, AZ | Welding | - |
| Steel House Bending, Welding | Indianapolis, IN | BendingWelding | - |
| Steel Plate Fabricators Milling, Turning, Bending, Laser, Welding, Waterjet, Metal AM | Knoxville, TN | MillingTurningBendingLaserWeldingWaterjetMetal AM | - |
| Steel Specialties Inc. Welding | El Paso, TX | Welding | - |
| Steel Tech Fabricator Welding | Rochester, NY | Welding | - |
| Steel Valley Fabricators, LLC Milling, Bending, Welding | Braddock, PA | MillingBendingWelding | - |
| Steel Werx Bending, Welding | Santa Clara, CA | BendingWelding | - |
| Steeltron Metal Works Bending, Welding | San Antonio, TX | BendingWelding | - |
| Sterling Machine Technologies Turning, Bending, Welding | Palmyra, PA | TurningBendingWelding | - |
| Still Waters Metal Fab LLC Bending, Welding | Spokane Valley, WA | BendingWelding | - |
| Structural Steel & Plate Fab Bending, Welding | North Salt Lake, UT | BendingWelding | - |
| Summit Machine Solutions Milling, Welding | Akron, OH | MillingWelding | - |
| Superior Machine & Tool Milling, Turning, Welding · ISO 9001 | Fort Wayne, IN | MillingTurningWelding | ISO 9001 |
| Superior Pipe Fabricators Welding | Los Angeles, CA | Welding | - |
| Superior Process Solutions Milling, Turning, Bending, Laser, Welding, Metal AM | Springfield, MO | MillingTurningBendingLaserWeldingMetal AM | - |
| Susquehanna Metal Work, LLC Milling, Bending, Welding, Stamping | Columbia, PA | MillingBendingWeldingStamping | - |