| In Tolerance Contract Manufacturing Milling, Turning, Bending · ISO 9001, AS9100, NADCAP | Cedar Rapids, IA | MillingTurningBending | ISO 9001, AS9100, NADCAP |
| Independence Machine & Tool LLC Milling, Turning, Grinding | Madison, IN | MillingTurningGrinding | - |
| Industrial Chrome Inc Milling, Turning, Laser, Bending, Welding, Grinding, Finishing, Assembly · ISO 9001 | Topeka, KS | MillingTurningLaserBendingWeldingGrindingFinishingAssembly | ISO 9001 |
| Industrial Experimental Technologies, LLC Welding, Stamping · ISO 9001 | Auburn Hills, MI | WeldingStamping | ISO 9001 |
| Industrial Fabricators Milling, Turning, Bending, Welding, Waterjet | Corpus Christi, TX | MillingTurningBendingWeldingWaterjet | - |
| Infocus CNC Machining, Inc Milling, Turning, Swiss · ISO 9001, AS9100 | Fountain Valley, CA | MillingTurningSwiss | ISO 9001, AS9100 |
| InSight Manufacturing Milling, Turning, Welding, Forging, Assembly | Murphys, CA | MillingTurningWeldingForgingAssembly | - |
| Instrument Development Corp Milling, Turning, EDM | Mukwonago, WI | MillingTurningEDM | - |
| Inter-Precision Mold Inc Milling, Turning, Welding, EDM, Grinding, Assembly | El Paso, TX | MillingTurningWeldingEDMGrindingAssembly | - |
| Interactive Manufacturing, Inc Milling, Turning, Waterjet, Welding, Finishing, Assembly | Central Point, OR | MillingTurningWaterjetWeldingFinishingAssembly | - |
| Inventery Precision Milling, Turning, Swiss, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Pasadena, CA | MillingTurningSwissFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Iridium Manufacturing Milling, Turning, Waterjet, EDM, Grinding · ISO 9001 | Washington, MI | MillingTurningWaterjetEDMGrinding | ISO 9001 |
| Ironbound Castings II, LLC Milling, Turning, Casting | Newark, NJ | MillingTurningCasting | - |
| Irwin Automation Inc Milling, Turning, Welding, EDM, Grinding | Greensburg, PA | MillingTurningWeldingEDMGrinding | - |
| J & N Metal Products, LLC Milling, Laser, Bending, Welding, EDM · ISO 9001 | Brazil, IN | MillingLaserBendingWeldingEDM | ISO 9001 |
| J & S Technologies Inc Milling, Turning, Grinding, Finishing · ISO 9001 | Nunica, MI | MillingTurningGrindingFinishing | ISO 9001 |
| J & T Manufacturing & Engineering Milling, Turning | San Diego, CA | MillingTurning | - |
| J and J Custom Machining L.L.C Milling, Turning · ISO 9001 | Camarillo, CA | MillingTurning | ISO 9001 |
| J Newell Corp Milling, Welding | Arlington, WA | MillingWelding | - |
| J P Corporation Milling, Turning · ISO 9001, AS9100 | Beech Grove, IN | MillingTurning | ISO 9001, AS9100 |
| J.i.t. Manufacturing, Inc Milling, Laser, Punching, Bending, Welding, Finishing, Assembly | Cowpens, SC | MillingLaserPunchingBendingWeldingFinishingAssembly | - |
| Jarvis Manufacturing, Inc Milling, Turning, EDM, Assembly · ISO 9001, ITAR | San Jose, CA | MillingTurningEDMAssembly | ISO 9001, ITAR |
| Jax Laser Solutions LLC Laser | Jacksonville, FL | Laser | - |
| Jax Precision Milling, Turning, Bending, Metal AM · ISO 9001, AS9100, ITAR | Jacksonville, FL | MillingTurningBendingMetal AM | ISO 9001, AS9100, ITAR |
| JC Custom Machining & Design Inc Milling, Turning, Welding, Grinding | Hillsboro, OR | MillingTurningWeldingGrinding | - |
| JC Macelroy Co Inc Milling, Punching, Bending, Welding, Grinding, Assembly | Piscataway, NJ | MillingPunchingBendingWeldingGrindingAssembly | - |
| JCB Precision, LLC Milling | Concord, NH | Milling | - |
| JD Machine Milling, Turning, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningBendingWeldingEDM | ISO 9001, AS9100, ITAR, CMMC |
| Jep Manufacturing LLC Milling, Turning, Welding · ISO 9001 | Rosenberg, TX | MillingTurningWelding | ISO 9001 |
| Jet Machine & Mfg Milling, Welding | Hamilton, OH | MillingWelding | - |
| Jet Speed Metals Bending, Welding | Westbrook, ME | BendingWelding | - |
| JJR Engineering & Fabrication Inc Milling, Turning, Bending, Welding, Stamping, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Woodinville, WA | MillingTurningBendingWeldingStampingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| JMG Tool LLC Milling, Turning, Laser, Welding, Finishing · ISO 9001, AS9100, ITAR | Loxahatchee, FL | MillingTurningLaserWeldingFinishing | ISO 9001, AS9100, ITAR |
| JMR Machining LLC Milling, Turning, Casting, Finishing | Athens, TX | MillingTurningCastingFinishing | - |
| John J Steuby Co Milling, Turning, Swiss, Welding, Stamping, Casting, EDM, Finishing · ISO 9001, ITAR | Hazelwood, MO | MillingTurningSwissWeldingStampingCastingEDMFinishing | ISO 9001, ITAR |
| Johnson Manufacturing Systems LLC Milling, Turning, Welding, Grinding | Miamisburg, OH | MillingTurningWeldingGrinding | - |
| Jolar Machine Shop Milling, Grinding, Finishing · ISO 9001 | Dickson City, PA | MillingGrindingFinishing | ISO 9001 |
| Jonaco Machine Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001 | Chaska, MN | MillingTurningSwissEDMGrinding | ISO 9001 |
| Jonesboro Tool & Die Co Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, EDM, Grinding · AS9100, ITAR, CMMC | Jonesboro, AR | MillingTurningLaserWaterjetBendingWeldingStampingEDMGrinding | AS9100, ITAR, CMMC |
| JR Metal Works LLC Laser, Waterjet, Welding · ISO 9001, AS9100, ITAR | Kewaunee, WI | LaserWaterjetWelding | ISO 9001, AS9100, ITAR |
| Jrev Enterprises LLC Milling, Turning, Waterjet · ITAR | Espanola, NM | MillingTurningWaterjet | ITAR |
| Justified Performance LLC Laser, Bending, Welding, Finishing, Assembly · ISO 9001 | Rocklin, CA | LaserBendingWeldingFinishingAssembly | ISO 9001 |
| JV Precision Machine Co Milling, EDM · ISO 9001, AS9100, ITAR | Seymour, CT | MillingEDM | ISO 9001, AS9100, ITAR |
| K & B Machining Inc Milling, Turning, Laser, Grinding, Finishing · ISO 9001, ITAR | Claremore, OK | MillingTurningLaserGrindingFinishing | ISO 9001, ITAR |
| K & H Precision Products Milling, Casting · ISO 9001 | Honeoye Falls, NY | MillingCasting | ISO 9001 |
| K C Machine Milling, Turning, Waterjet · ISO 9001, AS9100 | Excelsior Springs, MO | MillingTurningWaterjet | ISO 9001, AS9100 |
| K&S Machining Milling, Turning | Madison, AL | MillingTurning | - |
| Kam Tool & Die Milling, Turning, EDM, Grinding · ISO 9001 | Zebulon, NC | MillingTurningEDMGrinding | ISO 9001 |
| Kap Manufacturing, Inc Milling · ISO 9001 | San Dimas, CA | Milling | ISO 9001 |
| Kaydek Machining, Inc Milling, Turning, Finishing · ISO 9001, AS9100 | San Jose, CA | MillingTurningFinishing | ISO 9001, AS9100 |