| Ravelin Defense Milling, Turning, Bending, Laser, Welding, Waterjet · ISO 9001, AS9100, ITAR, CMMC | Green Bay, WI | MillingTurningBendingLaserWeldingWaterjet | ISO 9001, AS9100, ITAR, CMMC |
| Reinhardt Fabrication Laser, Welding | Dallas, TX | LaserWelding | - |
| Reno Iron Works Co Welding | Reno, NV | Welding | - |
| Rensberger Technologies Milling, Turning, EDM · AS9100, ITAR, CMMC | Sioux Falls, SD | MillingTurningEDM | AS9100, ITAR, CMMC |
| Reyco Precision Machining Welding, Metal AM · ISO 9001, AS9100 | Englewood, CO | WeldingMetal AM | ISO 9001, AS9100 |
| Richards Machining Co Inc Milling, Turning | Santa Clara, CA | MillingTurning | - |
| RivCut Milling, Turning, Bending, Metal AM · ISO 9001, AS9100, ITAR | Union City, CA | MillingTurningBendingMetal AM | ISO 9001, AS9100, ITAR |
| Rivers Metal Products Bending, Laser, Welding | Lincoln, NE | BendingLaserWelding | - |
| RJ Enterprises Milling, Turning, EDM · ISO 9001, AS9100, ITAR | Gardena, CA | MillingTurningEDM | ISO 9001, AS9100, ITAR |
| RJC Manufacturing Services LLC Milling, Turning, Bending, Welding | Irwin, PA | MillingTurningBendingWelding | - |
| Roemer Machine Milling, Welding | Davenport, IA | MillingWelding | - |
| Rosado Welding Inc. Welding | Dallas, TX | Welding | - |
| Rosko Manufacturing Milling, Turning, Metal AM | Grimes, IA | MillingTurningMetal AM | - |
| Ross Metal Works Welding | Houston, TX | Welding | - |
| S & H Machine Co Inc Milling, Turning | Buffalo, NY | MillingTurning | - |
| S&W Precision Machining LLC Milling, Turning · ISO 9001, AS9100, ITAR, CMMC | Commerce City, CO | MillingTurning | ISO 9001, AS9100, ITAR, CMMC |
| 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 | - |
| Seal Tex Welding | Dallas, TX | Welding | - |
| Seattle Makers Laser, Welding, Metal AM | Seattle, WA | LaserWeldingMetal AM | - |
| Selway Machine Tool Co Inc Milling, Turning, Metal AM | Salt Lake City, UT | MillingTurningMetal AM | - |
| SendCutSend Milling, Bending, Laser, Welding, Waterjet | Reno, NV | MillingBendingLaserWeldingWaterjet | - |
| Sepco Erie Milling, Turning, Stamping · ISO 9001 | Erie, PA | MillingTurningStamping | ISO 9001 |
| 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 |
| Sick Fab LLC Milling, Bending, Welding | Las Vegas, NV | MillingBendingWelding | - |
| Sigma Machine Inc. Milling, EDM | Kalamazoo, MI | MillingEDM | - |
| Skamar Machine Milling, Turning · ISO 9001 | Cleveland, OH | MillingTurning | ISO 9001 |
| Slim Haney Machining Inc Milling, Turning, Welding | Tulsa, OK | MillingTurningWelding | - |
| Solvers Manufacturing Turning, Bending, Welding | Springfield, NE | TurningBendingWelding | - |
| South Bend Form Tool Co Milling, Turning, EDM | South Bend, IN | MillingTurningEDM | - |
| 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 | - |
| Summit City Precision Machining LLC Milling, Turning, EDM · ISO 9001 | Fort Wayne, IN | MillingTurningEDM | ISO 9001 |
| 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 | - |
| Swan Island Sheet Metal Works Turning, Bending, Laser, Welding | Portland, OR | TurningBendingLaserWelding | - |
| Tampa Bay Machining Milling, Turning, Welding, EDM · ISO 9001, AS9100, ITAR | Tampa, FL | MillingTurningWeldingEDM | ISO 9001, AS9100, ITAR |
| Tarman Machine Company, Inc. Welding | Canal Winchester, OH | Welding | - |
| TBC Metalworks Bending, Laser, Welding | Green Bay, WI | BendingLaserWelding | - |
| TCMS Inc Milling, Turning, Welding | Oklahoma City, OK | MillingTurningWelding | - |
| TEKE Machine Corporation Milling, Turning · ISO 9001, AS9100 | Rochester, NY | MillingTurning | ISO 9001, AS9100 |
| Temco Precision Machining Milling, EDM · ISO 9001, AS9100 | Manchester, NH | MillingEDM | ISO 9001, AS9100 |