| Spring Grove Sheet Metal Bending, Laser, Welding | Cincinnati, OH | BendingLaserWelding | - |
| Spyco Industries Inc Milling, Turning, Waterjet, Grinding · ISO 9001 | Burr Ridge, IL | MillingTurningWaterjetGrinding | ISO 9001 |
| Square Deal Machining Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly | Marathon, NY | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | - |
| SRS Fabrication Inc. Milling, Turning, Bending, Welding, Waterjet | North Las Vegas, NV | MillingTurningBendingWeldingWaterjet | - |
| Stampede Die Corp Milling, Turning, Waterjet, Welding, Casting, EDM | Wayland, MI | MillingTurningWaterjetWeldingCastingEDM | - |
| Standard Machine, LLC Milling, Turning, Welding, Casting, Grinding, Finishing | Cleveland, OH | MillingTurningWeldingCastingGrindingFinishing | - |
| Steadfast Machine Milling, Turning · AS9100, ITAR | Bixby, OK | MillingTurning | AS9100, ITAR |
| Stehl Corp Punching, Bending, Welding | Phoenix, AZ | PunchingBendingWelding | - |
| Sterling Machine Technologies Turning, Bending, Welding | Palmyra, PA | TurningBendingWelding | - |
| Steward Machine Co., Inc Turning, Welding, Assembly | Birmingham, AL | TurningWeldingAssembly | - |
| Stines' Machine, Inc Milling, Turning · ISO 9001, ITAR | Vista, CA | MillingTurning | ISO 9001, ITAR |
| Strickland Industries Milling, Turning, Laser, Bending, Welding, Assembly | Mansfield, TX | MillingTurningLaserBendingWeldingAssembly | - |
| Strickland Machine Co LLC Milling, Turning, Welding, Stamping, Grinding, Finishing, Assembly | North Chesterfield, VA | MillingTurningWeldingStampingGrindingFinishingAssembly | - |
| Strong Forge & Fabrication, LLC Milling, Bending, Welding, Finishing | Batavia, NY | MillingBendingWeldingFinishing | - |
| Subtract LLC Milling, Turning, Swiss, Laser, Waterjet, Welding, EDM, Finishing | Muncie, IN | MillingTurningSwissLaserWaterjetWeldingEDMFinishing | - |
| Summit Machining Co., Ltd Milling, Turning, Welding, Stamping, Casting, Finishing | Mogadore, OH | MillingTurningWeldingStampingCastingFinishing | - |
| Superior Metal Products Inc Milling, Turning, Grinding · ISO 9001 | Louviers, CO | MillingTurningGrinding | ISO 9001 |
| Superior Precision Machining LLC Milling · ISO 9001, ITAR, ISO 13485 | Fremont, CA | Milling | ISO 9001, ITAR, ISO 13485 |
| Surge Manufacturing LLC Milling · ISO 9001, AS9100, ITAR, CMMC | Otsego, MN | Milling | ISO 9001, AS9100, ITAR, CMMC |
| Susquehanna Metal Work, LLC Milling, Bending, Welding, Stamping | Columbia, PA | MillingBendingWeldingStamping | - |
| Swan Island Sheet Metal Works Turning, Bending, Laser, Welding | Portland, OR | TurningBendingLaserWelding | - |
| Swihart Industries Milling, Turning · ISO 9001 | Dayton, OH | MillingTurning | ISO 9001 |
| Sylvester Sheet Metal Bending, Welding | Manchester, NH | BendingWelding | - |
| Sync Milling | Purcellville, VA | Milling | - |
| Synergy Manufacturing Services LLC Welding, Assembly | Grafton, WI | WeldingAssembly | - |
| Szabo Precision Milling, Turning · ISO 9001, AS9100 | Diamond Springs, CA | MillingTurning | ISO 9001, AS9100 |
| T & T Metals Milling, Laser, Punching, Bending, Welding, Finishing · ISO 9001 | Covina, CA | MillingLaserPunchingBendingWeldingFinishing | ISO 9001 |
| Tellma LLC Milling, Turning, Laser, Punching, Welding | Glenville, MN | MillingTurningLaserPunchingWelding | - |
| Teltron Engineering, Inc Laser, Punching, Bending, Welding, Assembly · AS9100, ITAR, CMMC | Taunton, MA | LaserPunchingBendingWeldingAssembly | AS9100, ITAR, CMMC |
| Thaler Machine Co LLC Milling, Turning, Welding, EDM, Grinding · ISO 9001, AS9100 | Springboro, OH | MillingTurningWeldingEDMGrinding | ISO 9001, AS9100 |
| Thomas W Springer Inc Milling, Turning, Swiss, Welding, Grinding · ISO 9001 | Landenberg, PA | MillingTurningSwissWeldingGrinding | ISO 9001 |
| Thompson Machine Bending, Stamping · ISO 9001 | Albuquerque, NM | BendingStamping | ISO 9001 |
| Three Rivers Precision, LLC Welding, Assembly · ISO 9001 | East Liberty, PA | WeldingAssembly | ISO 9001 |
| Toledo Metal Spinning Company Milling, Bending, Laser, Welding, Stamping · ISO 9001 | Toledo, OH | MillingBendingLaserWeldingStamping | ISO 9001 |
| Top Machining, Inc Milling, Turning, Welding, Finishing, Assembly · ISO 9001, AS9100, ITAR | Santa Clara, CA | MillingTurningWeldingFinishingAssembly | ISO 9001, AS9100, ITAR |
| Total Machining USA Inc Bending, Welding · ISO 9001, AS9100, ITAR | Oakland Park, FL | BendingWelding | ISO 9001, AS9100, ITAR |
| Toth Industries Inc Milling, Turning, Bending, Casting · ISO 9001 | Toledo, OH | MillingTurningBendingCasting | ISO 9001 |
| Tozli Machine Milling, Welding, Finishing · ISO 9001, ITAR, CMMC | Surprise, AZ | MillingWeldingFinishing | ISO 9001, ITAR, CMMC |
| Trans Machine Technologies SC Milling, Turning, Bending, Laser, Welding, EDM, Casting · ISO 9001 | Greenville, SC | MillingTurningBendingLaserWeldingEDMCasting | ISO 9001 |
| Tridecs Corp Milling, Swiss, EDM, Grinding, Finishing, Assembly · ISO 9001 | Hayward, CA | MillingSwissEDMGrindingFinishingAssembly | ISO 9001 |
| Trident Precision Manufacturing Inc Welding, Stamping, Finishing, Assembly · ISO 9001, AS9100, ITAR, ISO 13485 | Webster, NY | WeldingStampingFinishingAssembly | ISO 9001, AS9100, ITAR, ISO 13485 |
| True Position Manufacturing Inc Turning, Welding · ISO 9001 | Davenport, IA | TurningWelding | ISO 9001 |
| U.S. Chrome Corporation of Ohio Grinding, Finishing · ISO 9001, NADCAP | Dayton, OH | GrindingFinishing | ISO 9001, NADCAP |
| Ultimate Hydroforming, Inc Laser, Welding, Stamping · ISO 9001, AS9100, ITAR, NADCAP | Sterling Heights, MI | LaserWeldingStamping | ISO 9001, AS9100, ITAR, NADCAP |
| United Machining Services Inc Welding · ISO 9001, AS9100 | Conroe, TX | Welding | ISO 9001, AS9100 |
| United Metal Fabricators Inc Bending, Welding · ISO 9001, ITAR | Cleveland, OH | BendingWelding | ISO 9001, ITAR |
| United Standard Industries Inc Milling, Turning, Welding, Grinding, Finishing · ISO 9001, AS9100 | Glenview, IL | MillingTurningWeldingGrindingFinishing | ISO 9001, AS9100 |
| US Aluminum Castings Milling, Turning, Casting, Grinding, Finishing, Assembly · ISO 9001, ITAR, NADCAP, IATF 16949 | Entiat, WA | MillingTurningCastingGrindingFinishingAssembly | ISO 9001, ITAR, NADCAP, IATF 16949 |
| USA Machine Inc Milling, Assembly · AS9100 | Royse City, TX | MillingAssembly | AS9100 |
| Vinaco Precision Machining, LLC Milling, Turning, Grinding, Finishing · ISO 9001, AS9100, NADCAP | Chatsworth, CA | MillingTurningGrindingFinishing | ISO 9001, AS9100, NADCAP |