| MCW Certified Welding Ltd Punching, Bending, Welding | Delta, OH | PunchingBendingWelding | - |
| Mechanical Development Company, Incorporated Welding | Salem, VA | Welding | - |
| Melton Sheet Metal Bending, Welding | Fresno, CA | BendingWelding | - |
| Merritt Welding & Fabrication Bending, Welding | Denver, CO | BendingWelding | - |
| Michael R Gesellschap Milling, Turning, Welding | Belle, MO | MillingTurningWelding | - |
| Mid America Steel Inc Milling, Bending, Welding, Casting | Fargo, ND | MillingBendingWeldingCasting | - |
| Models & Tools Inc Milling, Turning, Welding · AS9100 | Shelby Township, MI | MillingTurningWelding | AS9100 |
| Morena Welding Inc Welding | San Diego, CA | Welding | - |
| Nelgo Manufacturing Co Milling, Turning, Punching, Welding · ISO 9001, AS9100, ITAR | Oceanside, CA | MillingTurningPunchingWelding | ISO 9001, AS9100, ITAR |
| Nocturnal Welding Welding | Camarillo, CA | Welding | - |
| Northfield Manufacturing, Inc Welding, Casting | Westland, MI | WeldingCasting | - |
| O'Connell Machinery Co Inc Milling, Welding | Buffalo, NY | MillingWelding | - |
| Olson & Co. Steel Welding | Fresno, CA | Welding | - |
| Ottenweller Company, Inc. Bending, Laser, Welding · ISO 9001 | Fort Wayne, IN | BendingLaserWelding | ISO 9001 |
| P&M Steel Company Welding | Sioux Falls, SD | Welding | - |
| Pascetti Steel Design, Inc. Bending, Welding | Albuquerque, NM | BendingWelding | - |
| Pennsylvania Steel Co. Inc. Welding · ISO 9001 | Birmingham, AL | Welding | ISO 9001 |
| Perforated Panels Laser, Waterjet, Bending, Welding | Pacoima, CA | LaserWaterjetBendingWelding | - |
| Pgi Steel Milling, Turning, Welding, Grinding, Finishing · ISO 9001, ITAR | Birmingham, AL | MillingTurningWeldingGrindingFinishing | ISO 9001, ITAR |
| Phoenix Welding Welding | Portland, ME | Welding | - |
| Pierce Steel Fabricators & Machining, Inc Punching, Bending, Welding, Finishing | Olean, NY | PunchingBendingWeldingFinishing | - |
| Premier Steel Bending, Welding | Anaheim, CA | BendingWelding | - |
| Pro-Weld LLC Bending, Welding | Lexington, KY | BendingWelding | - |
| QSR Steel Corporation Welding | Hartford, CT | Welding | - |
| Quality Welding & Fabrication, LLC Bending, Welding | Lima, OH | BendingWelding | - |
| Quality Welding Service Inc Laser, Welding | Suamico, WI | LaserWelding | - |
| Ravelin Defense Milling, Turning, Bending, Laser, Welding, Waterjet · ISO 9001, AS9100, ITAR, CMMC | Green Bay, WI | MillingTurningBendingLaserWeldingWaterjet | ISO 9001, AS9100, ITAR, CMMC |
| Reliance Machining Inc Milling, Turning, Welding, Grinding | Minneapolis, MN | MillingTurningWeldingGrinding | - |
| Rentiel Precision Laser Cutting L.L.C Milling, Laser, Welding | Tacoma, WA | MillingLaserWelding | - |
| Rhinehart Development Corp Laser, Punching, Bending, Welding, Stamping, Finishing · ISO 9001 | Spencerville, IN | LaserPunchingBendingWeldingStampingFinishing | ISO 9001 |
| Roncelli Plastics Inc Welding, Stamping, Assembly · ISO 9001, ITAR, ISO 13485, CMMC | Monrovia, CA | WeldingStampingAssembly | ISO 9001, ITAR, ISO 13485, CMMC |
| Rosado Welding Inc. Welding | Dallas, TX | Welding | - |
| Selective Industries, Inc Laser, Welding, Stamping · ISO 9001 | Marine City, MI | LaserWeldingStamping | ISO 9001 |
| Service Steel, Inc. Welding | Huntsville, AL | Welding | - |
| Shelby Supply Co LLC Welding · ISO 9001 | Tolland, CT | Welding | ISO 9001 |
| Sintel Inc Laser, Punching, Bending, Welding, Finishing, Assembly | Spring Lake, MI | LaserPunchingBendingWeldingFinishingAssembly | - |
| Slagel Manufacturing, Inc Bending, Welding, Finishing · ISO 9001 | Forrest, IL | BendingWeldingFinishing | ISO 9001 |
| SOS Steel Co Inc Welding | Santa Clara, CA | Welding | - |
| Specialty Steel Supply Co., Inc Punching, Bending, Welding | Fairless Hills, PA | PunchingBendingWelding | - |
| SpecWeld Milling, Welding, Assembly · ISO 9001 | Lake Orion, MI | MillingWeldingAssembly | ISO 9001 |
| 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 Tech Fabricator Welding | Rochester, NY | Welding | - |
| Steel Valley Fabricators, LLC Milling, Bending, Welding | Braddock, PA | MillingBendingWelding | - |
| Steel Werx Bending, Welding | Santa Clara, CA | BendingWelding | - |
| Steel-Craft Corp. of Hartford Milling, Laser, Punching, Bending, Welding, Stamping, Finishing | Hartford, WI | MillingLaserPunchingBendingWeldingStampingFinishing | - |
| Steelcrest Precision, Inc Milling, Turning, Swiss, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100 | Wauseon, OH | MillingTurningSwissWeldingEDMGrindingAssembly | ISO 9001, AS9100 |
| Steelhead Composites, Inc Welding · ISO 9001, AS9100 | Golden, CO | Welding | ISO 9001, AS9100 |
| Steeltron Metal Works Bending, Welding | San Antonio, TX | BendingWelding | - |