| Raleigh Mechanical & Metals Turning, Bending, Welding | Raleigh, NC | TurningBendingWelding | - |
| Rand Machine Works Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Ravelin Defense Milling, Turning, Bending, Laser, Welding, Waterjet · ISO 9001, AS9100, ITAR, CMMC | Green Bay, WI | MillingTurningBendingLaserWeldingWaterjet | ISO 9001, AS9100, ITAR, CMMC |
| RDR Precision Tech Milling, Turning · ISO 9001 | Bakersfield, CA | MillingTurning | ISO 9001 |
| Remarc Manufacturing Milling, Turning, Welding, Waterjet, Metal AM | Reno, NV | MillingTurningWeldingWaterjetMetal AM | - |
| Rensberger Technologies Milling, Turning, EDM · AS9100, ITAR, CMMC | Sioux Falls, SD | MillingTurningEDM | AS9100, ITAR, CMMC |
| Restless Machines LLC Milling, Turning | Greenville, SC | MillingTurning | - |
| Richards Machining Co Inc Milling, Turning | Santa Clara, CA | MillingTurning | - |
| Richards Sheet Metal Turning, Bending, Laser, Welding, Stamping · ISO 9001 | Ogden, UT | TurningBendingLaserWeldingStamping | ISO 9001 |
| RivCut Milling, Turning, Bending, Metal AM · ISO 9001, AS9100, ITAR | Union City, CA | MillingTurningBendingMetal AM | ISO 9001, AS9100, ITAR |
| 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 | - |
| Rosko Manufacturing Milling, Turning, Metal AM | Grimes, IA | MillingTurningMetal AM | - |
| S & H Machine Co Inc Milling, Turning | Buffalo, NY | MillingTurning | - |
| S & S Machine Milling, Turning, Bending, Welding, Waterjet, EDM | Amherst, NH | MillingTurningBendingWeldingWaterjetEDM | - |
| S&W Precision Machining LLC Milling, Turning · ISO 9001, AS9100, ITAR, CMMC | Commerce City, CO | MillingTurning | ISO 9001, AS9100, ITAR, CMMC |
| Sanders Metal Products Inc Milling, Turning, Bending, Welding | Fargo, ND | MillingTurningBendingWelding | - |
| Seaberg Industries Turning, Bending, Laser, Welding · ISO 9001 | Davenport, IA | TurningBendingLaserWelding | ISO 9001 |
| Selway Machine Tool Co Inc Milling, Turning, Metal AM | Salt Lake City, UT | MillingTurningMetal AM | - |
| 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 |
| Shamrock Precision Milling, Turning, Bending · ISO 9001, AS9100 | Dallas, TX | MillingTurningBending | ISO 9001, AS9100 |
| 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 | - |
| Skamar Machine Milling, Turning · ISO 9001 | Cleveland, OH | MillingTurning | ISO 9001 |
| 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 | - |
| South Bend Form Tool Co Milling, Turning, EDM | South Bend, IN | MillingTurningEDM | - |
| 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 |
| Specialty Precision Machining Milling, Turning, Laser · ISO 9001 | Stockton, CA | MillingTurningLaser | ISO 9001 |
| SRS Fabrication Inc. Milling, Turning, Bending, Welding, Waterjet | North Las Vegas, NV | MillingTurningBendingWeldingWaterjet | - |
| Steel Plate Fabricators Milling, Turning, Bending, Laser, Welding, Waterjet, Metal AM | Knoxville, TN | MillingTurningBendingLaserWeldingWaterjetMetal AM | - |
| Sterling Machine Technologies Turning, Bending, Welding | Palmyra, PA | TurningBendingWelding | - |
| Summit City Precision Machining LLC Milling, Turning, EDM · ISO 9001 | Fort Wayne, IN | MillingTurningEDM | ISO 9001 |
| Summit Machine Tool LLC Milling, Turning | Oklahoma City, OK | MillingTurning | - |
| Superior Machine & Tool Milling, Turning, Welding · ISO 9001 | Fort Wayne, IN | MillingTurningWelding | ISO 9001 |
| 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 | - |
| Swihart Industries Milling, Turning · ISO 9001 | Dayton, OH | MillingTurning | ISO 9001 |
| Swiss Technologies Inc. Milling, Turning, Welding, Stamping · ISO 9001 | Knoxville, TN | MillingTurningWeldingStamping | ISO 9001 |
| Tampa Bay Machining Milling, Turning, Welding, EDM · ISO 9001, AS9100, ITAR | Tampa, FL | MillingTurningWeldingEDM | ISO 9001, AS9100, ITAR |
| TCMS Inc Milling, Turning, Welding | Oklahoma City, OK | MillingTurningWelding | - |
| Tecma Milling, Turning, Welding, Waterjet, EDM, Stamping, Casting · ISO 9001, AS9100, ITAR, NADCAP | Sacramento, CA | MillingTurningWeldingWaterjetEDMStampingCasting | ISO 9001, AS9100, ITAR, NADCAP |
| TEKE Machine Corporation Milling, Turning · ISO 9001, AS9100 | Rochester, NY | MillingTurning | ISO 9001, AS9100 |
| Teton Machine Co Milling, Turning · ISO 9001, AS9100, ITAR | Payette, ID | MillingTurning | ISO 9001, AS9100, ITAR |
| The Gent Machine Company Milling, Turning · ISO 9001, IATF 16949 | Cleveland, OH | MillingTurning | ISO 9001, IATF 16949 |
| Theonics Milling, Turning, Bending, Welding, EDM · AS9100, ITAR, ISO 13485 | Huntsville, AL | MillingTurningBendingWeldingEDM | AS9100, ITAR, ISO 13485 |