| Infinity Precision Inc Milling, Turning, Waterjet, Bending, Grinding · ISO 9001, AS9100 | Simi Valley, CA | MillingTurningWaterjetBendingGrinding | ISO 9001, AS9100 |
| Infinity Precision Machining LLC Milling, Turning | Buffalo, NY | MillingTurning | - |
| Infocus CNC Machining, Inc Milling, Turning, Swiss · ISO 9001, AS9100 | Fountain Valley, CA | MillingTurningSwiss | ISO 9001, AS9100 |
| Innovated Metal Fabrication, Inc Turning, Bending, Laser, Welding | Maplewood, MN | TurningBendingLaserWelding | - |
| Innovation Alley Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| Insource Design & Manufacturing Technologies, LLC Milling, Turning, Assembly · ISO 9001, ITAR | Manchester, NH | MillingTurningAssembly | ISO 9001, ITAR |
| Inspirnetics, Inc Milling, Turning | Rancho Cucamonga, CA | MillingTurning | - |
| Integra Cast Milling, Turning, Welding, Casting, Finishing, Assembly · ISO 9001, NADCAP | New Britain, CT | MillingTurningWeldingCastingFinishingAssembly | ISO 9001, NADCAP |
| Integrated Components Inc Milling, Turning | Wichita, KS | MillingTurning | - |
| Integrated Machining Co Milling, Turning, Welding, EDM, Grinding · ISO 9001, ITAR | Albuquerque, NM | MillingTurningWeldingEDMGrinding | ISO 9001, ITAR |
| Inter-Precision Mold Inc Milling, Turning, Welding, EDM, Grinding, Assembly | El Paso, TX | MillingTurningWeldingEDMGrindingAssembly | - |
| Intrepid Machine, Inc Milling, Turning · ISO 9001, AS9100 | Brooksville, FL | MillingTurning | ISO 9001, AS9100 |
| Inventery Precision Milling, Turning, Swiss, Finishing, Assembly · ISO 9001, AS9100, ITAR, CMMC | Pasadena, CA | MillingTurningSwissFinishingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Iowa Metal Spinners Milling, Turning, Laser, Welding, Stamping · ISO 9001 | Cedar Falls, IA | MillingTurningLaserWeldingStamping | ISO 9001 |
| IPMI Manufacturing & Engineering Milling, Turning, Welding | Buckner, MO | MillingTurningWelding | - |
| Ironbound Castings II, LLC Milling, Turning, Casting | Newark, NJ | MillingTurningCasting | - |
| Isembard Corporation Milling, Turning · ISO 9001, AS9100, ITAR, CMMC | Carrollton, TX | MillingTurning | ISO 9001, AS9100, ITAR, CMMC |
| J A-Co Machine Works, LLC Milling, Turning, Swiss, Welding, Finishing, Assembly · ISO 9001, AS9100, ITAR, NADCAP, ISO 13485 | Scotts Valley, CA | MillingTurningSwissWeldingFinishingAssembly | ISO 9001, AS9100, ITAR, NADCAP, ISO 13485 |
| J P Corporation Milling, Turning · ISO 9001, AS9100 | Beech Grove, IN | MillingTurning | ISO 9001, AS9100 |
| J W Machine & Fab LLC Milling, Turning, Welding, Grinding | Fountain Inn, SC | MillingTurningWeldingGrinding | - |
| J. I. Machine Co., Inc Milling, Turning, Swiss · ISO 9001, AS9100, ITAR | San Diego, CA | MillingTurningSwiss | ISO 9001, AS9100, ITAR |
| J. L. Machine, LLC Milling, Turning | Zebulon, NC | MillingTurning | - |
| J.B. Anderson & Son, Inc Milling, Turning, Welding, Assembly | Irwin, PA | MillingTurningWeldingAssembly | - |
| J&M Machining Milling, Turning, Welding, Casting, Finishing · ISO 9001 | Norton Shores, MI | MillingTurningWeldingCastingFinishing | ISO 9001 |
| Jacksonville Machine, Inc Milling, Turning, Welding, Grinding · ISO 9001 | Jacksonville, IL | MillingTurningWeldingGrinding | ISO 9001 |
| Jaco Engineering Milling, Turning, Bending, Welding, EDM, Grinding, Finishing, Assembly · NADCAP | Anaheim, CA | MillingTurningBendingWeldingEDMGrindingFinishingAssembly | NADCAP |
| Jaffa Precision Engineering Inc Milling, Turning, Swiss, Welding, Grinding, Finishing · ISO 9001 | Riverside, CA | MillingTurningSwissWeldingGrindingFinishing | ISO 9001 |
| Jarvis Manufacturing, Inc Milling, Turning, EDM, Assembly · ISO 9001, ITAR | San Jose, CA | MillingTurningEDMAssembly | ISO 9001, ITAR |
| Jax Precision Milling, Turning, Bending, Metal AM · ISO 9001, AS9100, ITAR | Jacksonville, FL | MillingTurningBendingMetal AM | ISO 9001, AS9100, ITAR |
| JB Precision Machining, Inc Milling, Turning | Brentwood, NY | MillingTurning | - |
| JBC Machine Inc Milling, Turning, Welding, Finishing | Hortonville, WI | MillingTurningWeldingFinishing | - |
| JC Custom Machining & Design Inc Milling, Turning, Welding, Grinding | Hillsboro, OR | MillingTurningWeldingGrinding | - |
| JC Machine, Inc Milling, Turning, Swiss, Laser, Bending, Welding | Lakeland, FL | MillingTurningSwissLaserBendingWelding | - |
| JD Machine Milling, Turning, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningBendingWeldingEDM | ISO 9001, AS9100, ITAR, CMMC |
| Jeglinski Group Inc Milling, Turning, Welding, EDM, Grinding, Assembly · ISO 9001 | Meadville, PA | MillingTurningWeldingEDMGrindingAssembly | ISO 9001 |
| Jenkins Machine Inc Milling, Turning, EDM, Grinding, Finishing | Bethlehem, PA | MillingTurningEDMGrindingFinishing | - |
| Jep Manufacturing LLC Milling, Turning, Welding · ISO 9001 | Rosenberg, TX | MillingTurningWelding | ISO 9001 |
| Jet Helseth Manufacturing Inc Turning, EDM, Finishing, Assembly · ISO 9001, ITAR | Deland, FL | TurningEDMFinishingAssembly | ISO 9001, ITAR |
| Jet Machined Products, LLC Milling, Turning, Stamping, Grinding · ISO 9001, ITAR | East Bridgewater, MA | MillingTurningStampingGrinding | ISO 9001, ITAR |
| Jetfab LLC Milling, Turning, Laser, Waterjet, Punching, Bending, Welding | Lowell, MA | MillingTurningLaserWaterjetPunchingBendingWelding | - |
| Jewett Machine Milling, Turning, Welding · ISO 9001 | Richmond, VA | MillingTurningWelding | ISO 9001 |
| JJR Engineering & Fabrication Inc Milling, Turning, Bending, Welding, Stamping, Finishing, Assembly · ISO 9001, AS9100, NADCAP | Woodinville, WA | MillingTurningBendingWeldingStampingFinishingAssembly | ISO 9001, AS9100, NADCAP |
| JK Pulley Co Inc Milling, Turning, Welding | Saint Louis, MO | MillingTurningWelding | - |
| JMR Machining LLC Milling, Turning, Casting, Finishing | Athens, TX | MillingTurningCastingFinishing | - |
| Joels Machine Shop Inc Milling, Turning, Grinding | El Monte, CA | MillingTurningGrinding | - |
| John J Steuby Co Milling, Turning, Swiss, Welding, Stamping, Casting, EDM, Finishing · ISO 9001, ITAR | Hazelwood, MO | MillingTurningSwissWeldingStampingCastingEDMFinishing | ISO 9001, ITAR |
| Johnson Manufacturing Milling, Turning, Grinding · AS9100 | Huntington Beach, CA | MillingTurningGrinding | AS9100 |
| Jonaco Machine Inc Milling, Turning, Swiss, EDM, Grinding · ISO 9001 | Chaska, MN | MillingTurningSwissEDMGrinding | ISO 9001 |
| Jones Co Machining Milling, Turning, Welding, Assembly | Hannibal, MO | MillingTurningWeldingAssembly | - |
| Jonesboro Tool & Die Co Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Stamping, EDM, Grinding · AS9100, ITAR, CMMC | Jonesboro, AR | MillingTurningLaserWaterjetBendingWeldingStampingEDMGrinding | AS9100, ITAR, CMMC |