| Silicon Precision Machining Inc Milling, Turning | Fremont, CA | MillingTurning | - |
| Slag Factory Milling, Laser, Welding | Oroville, CA | MillingLaserWelding | - |
| SLT Machine Works LLC Milling, Turning · ISO 9001, AS9100 | Stafford, TX | MillingTurning | ISO 9001, AS9100 |
| Smith Brothers Tool Company Milling, Welding · ISO 9001, AS9100, ITAR | Shelby Township, MI | MillingWelding | ISO 9001, AS9100, ITAR |
| SMR Manufacturing&engineering LLC Milling, Laser | Clermont, FL | MillingLaser | - |
| Sound Manufacturing, Inc Milling, Laser, Punching, Bending, Welding, Assembly · ISO 9001 | Old Saybrook, CT | MillingLaserPunchingBendingWeldingAssembly | ISO 9001 |
| Southeastern Machining Milling, Turning, Welding · ISO 9001 | Worthington, OH | MillingTurningWelding | ISO 9001 |
| Southwest Waterjet and Laser Milling, Laser, Waterjet, Bending | Phoenix, AZ | MillingLaserWaterjetBending | - |
| Sparton Technology Corp Milling, Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001, AS9100 | Hudson, NH | MillingTurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001, AS9100 |
| Square Deal Machining Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly | Marathon, NY | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | - |
| Standard Machine, LLC Milling, Turning, Welding, Casting, Grinding, Finishing | Cleveland, OH | MillingTurningWeldingCastingGrindingFinishing | - |
| Stanfordville Machine & Manufacturing Co Inc Milling, Turning, Swiss, Welding, EDM, Grinding · ISO 9001, AS9100 | Poughkeepsie, NY | MillingTurningSwissWeldingEDMGrinding | ISO 9001, AS9100 |
| 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 Metal Corp Milling, Turning, Laser, Waterjet, Bending, EDM, Finishing · ISO 9001 | Nampa, ID | MillingTurningLaserWaterjetBendingEDMFinishing | ISO 9001 |
| Steen Machining, Inc Milling, Turning, Finishing | Westminster, CO | MillingTurningFinishing | - |
| Stephens Precision, Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Bradford, VT | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| Streich Bros Inc Milling, Welding | Tacoma, WA | MillingWelding | - |
| Strickland Industries Milling, Turning, Laser, Bending, Welding, Assembly | Mansfield, TX | MillingTurningLaserBendingWeldingAssembly | - |
| Subtract LLC Milling, Turning, Swiss, Laser, Waterjet, Welding, EDM, Finishing | Muncie, IN | MillingTurningSwissLaserWaterjetWeldingEDMFinishing | - |
| Summit Machine Company Milling, Turning, Welding, Finishing · ISO 9001 | Alverton, PA | MillingTurningWeldingFinishing | ISO 9001 |
| Summit Products Inc Milling, Bending, Welding, Finishing | Altoona, IA | MillingBendingWeldingFinishing | - |
| Superior Process Solutions Milling, Turning, Bending, Laser, Welding, Metal AM | Springfield, MO | MillingTurningBendingLaserWeldingMetal AM | - |
| Surfacemode, Inc Milling · ISO 9001, AS9100, ITAR | San Diego, CA | Milling | ISO 9001, AS9100, ITAR |
| Surfix Inc Milling, Bending, Welding | Palm Bay, FL | MillingBendingWelding | - |
| Susquehanna Metal Work, LLC Milling, Bending, Welding, Stamping | Columbia, PA | MillingBendingWeldingStamping | - |
| Swanton Welding & Machining Co Inc Milling, Laser, Bending, Welding, Finishing, Assembly | Swanton, OH | MillingLaserBendingWeldingFinishingAssembly | - |
| Swiss Wire EDM Milling, Turning, Welding, EDM · ISO 9001, ITAR, NADCAP | Costa Mesa, CA | MillingTurningWeldingEDM | ISO 9001, ITAR, NADCAP |
| Swissturn/usa, Inc Milling, Turning, Swiss, Grinding, Finishing · ISO 9001, ITAR, CMMC | Oxford, MA | MillingTurningSwissGrindingFinishing | ISO 9001, ITAR, CMMC |
| T & T Metals Milling, Laser, Punching, Bending, Welding, Finishing · ISO 9001 | Covina, CA | MillingLaserPunchingBendingWeldingFinishing | ISO 9001 |
| T-Tygart Industries, Inc Milling, Turning, Bending, Welding, Grinding | Carmichaels, PA | MillingTurningBendingWeldingGrinding | - |
| Tanksley Machine & Tool, Inc Milling, Turning, Laser, Welding, EDM, Grinding · AS9100 | Decatur, AL | MillingTurningLaserWeldingEDMGrinding | AS9100 |
| Taylor EDM Specialties LLC Milling, EDM, Grinding | Wauconda, IL | MillingEDMGrinding | - |
| Team Technologies Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001, AS9100 | Albuquerque, NM | MillingTurningWeldingEDMGrindingAssembly | ISO 9001, AS9100 |
| Tec Inc Milling, Turning, Swiss, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Frederick, MD | MillingTurningSwissLaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Tech Heavy Industries, Inc Milling, Waterjet, Bending, Welding | Riverside, WA | MillingWaterjetBendingWelding | - |
| Tecma Milling, Turning, Welding, Waterjet, EDM, Stamping, Casting · ISO 9001, AS9100, ITAR, NADCAP | Sacramento, CA | MillingTurningWeldingWaterjetEDMStampingCasting | ISO 9001, AS9100, ITAR, NADCAP |
| Tellma LLC Milling, Turning, Laser, Punching, Welding | Glenville, MN | MillingTurningLaserPunchingWelding | - |
| Tennessee Tool Works LLC Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, EDM, Grinding | Murfreesboro, TN | MillingTurningLaserWaterjetBendingWeldingStampingEDMGrinding | - |
| Texoma Industries of Graham, LLC Milling, Turning, Bending, Welding | Graham, TX | MillingTurningBendingWelding | - |
| Thermo-Craft Engineering Corp Milling, Turning, Waterjet, Punching, Bending, Welding, Grinding, Assembly | Lynn, MA | MillingTurningWaterjetPunchingBendingWeldingGrindingAssembly | - |
| Third Reef Machining and Engineering Ltd. Co Milling, Bending, Welding, Finishing | Cottonwood Heights, UT | MillingBendingWeldingFinishing | - |
| Thomason Machine Works Inc Milling, Turning, EDM · ISO 9001 | Rockford, IL | MillingTurningEDM | ISO 9001 |
| Thompson Precision Inc Milling, Turning, Welding · AS9100 | Kalispell, MT | MillingTurningWelding | AS9100 |
| Tico Tooling LLC Milling, Turning, Stamping, EDM, Grinding · ISO 9001 | San Marcos, TX | MillingTurningStampingEDMGrinding | ISO 9001 |
| Tidewater Machine Co Milling, Turning, EDM | White Plains, MD | MillingTurningEDM | - |
| Tin-Mar, Inc Milling, Turning, Waterjet, Welding, EDM · ISO 9001, AS9100 | Huntsville, AL | MillingTurningWaterjetWeldingEDM | ISO 9001, AS9100 |
| Titletown Manufacturing LLC Milling, Welding | Green Bay, WI | MillingWelding | - |
| Tobar Industries Milling, Turning, Bending, Welding | San Jose, CA | MillingTurningBendingWelding | - |
| Toledo Metal Spinning Company Milling, Bending, Laser, Welding, Stamping · ISO 9001 | Toledo, OH | MillingBendingLaserWeldingStamping | ISO 9001 |