| Horizon Tech Industries Inc Milling, Turning, Swiss, Finishing | Fort Worth, TX | MillingTurningSwissFinishing | - |
| Houston Foundry Manufacturing, L.L.C Milling, Welding, Casting · ISO 9001, AS9100 | Houston, TX | MillingWeldingCasting | ISO 9001, AS9100 |
| HTT, Inc Laser, Welding, Stamping, EDM, Grinding, Finishing | Sheboygan, WI | LaserWeldingStampingEDMGrindingFinishing | - |
| IFT Worldwide Milling, Stamping, Finishing | South Bend, IN | MillingStampingFinishing | - |
| Imagineering Machine Inc Milling, Turning, Casting · NADCAP | St Louis Park, MN | MillingTurningCasting | NADCAP |
| In Tolerance Contract Manufacturing Milling, Turning, Bending · ISO 9001, AS9100, NADCAP | Cedar Rapids, IA | MillingTurningBending | ISO 9001, AS9100, NADCAP |
| Indy Cast Alloys, Inc Casting | Indianapolis, IN | Casting | - |
| Inno-Tec Welding & Fabrication LLC Welding | Springfield, OH | Welding | - |
| 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 | - |
| Iowa Metal Spinners Milling, Turning, Laser, Welding, Stamping · ISO 9001 | Cedar Falls, IA | MillingTurningLaserWeldingStamping | ISO 9001 |
| IronStrong Metal Fabrication LLC Milling, Bending, Laser, Welding | Lancaster, PA | MillingBendingLaserWelding | - |
| J.V. Manufacturing Co Inc Stamping, EDM, Grinding · ISO 9001 | Natrona Heights, PA | StampingEDMGrinding | ISO 9001 |
| Jaffa Precision Engineering Inc Milling, Turning, Swiss, Welding, Grinding, Finishing · ISO 9001 | Riverside, CA | MillingTurningSwissWeldingGrindingFinishing | ISO 9001 |
| Jax Fab Shop LLC Welding | Jacksonville, FL | Welding | - |
| JD Laser Inc Laser, Bending | Hartford, WI | LaserBending | - |
| Jetfab LLC Milling, Turning, Laser, Waterjet, Punching, Bending, Welding | Lowell, MA | MillingTurningLaserWaterjetPunchingBendingWelding | - |
| JMC Acquisition LLC Milling, Turning, Swiss, Welding · ISO 9001, AS9100, ISO 13485 | Sanford, NC | MillingTurningSwissWelding | ISO 9001, AS9100, ISO 13485 |
| JMS Machine, Inc Milling, Turning, EDM, Grinding | Columbia City, IN | MillingTurningEDMGrinding | - |
| John W. McDougall Co. Bending, Laser, Welding · ISO 9001 | Nashville, TN | BendingLaserWelding | ISO 9001 |
| Johnson Manufacturing Milling, Turning, Grinding · AS9100 | Huntington Beach, CA | MillingTurningGrinding | AS9100 |
| Jrev Enterprises LLC Milling, Turning, Waterjet · ITAR | Espanola, NM | MillingTurningWaterjet | ITAR |
| JRS Precision Machine & Design LLC Milling, Turning | Lakeville, MA | MillingTurning | - |
| JV Precision Machine Co Milling, EDM · ISO 9001, AS9100, ITAR | Seymour, CT | MillingEDM | ISO 9001, AS9100, ITAR |
| Kam Tool & Die Milling, Turning, EDM, Grinding · ISO 9001 | Zebulon, NC | MillingTurningEDMGrinding | ISO 9001 |
| Kennebec Technologies Milling, Grinding, Assembly | Augusta, ME | MillingGrindingAssembly | - |
| Kenney Industries, Inc. Bending, Welding · ISO 9001, NADCAP | Dallas, TX | BendingWelding | ISO 9001, NADCAP |
| Kennley Corp Milling, Turning, Grinding, Finishing | North Chesterfield, VA | MillingTurningGrindingFinishing | - |
| Kent Machine Milling, EDM, Grinding | Indianapolis, IN | MillingEDMGrinding | - |
| Kimura Foundry America, Inc Casting, Metal AM | Shelbyville, IN | CastingMetal AM | - |
| Kinetik Systems LLC Milling, Turning, Welding | Tucson, AZ | MillingTurningWelding | - |
| Kinross Fab & Machine Inc Milling, Turning, Laser, Welding, Grinding, Finishing | Kincheloe, MI | MillingTurningLaserWeldingGrindingFinishing | - |
| Kinship Precision LLC Milling, Turning, Swiss, Laser · ISO 9001, ISO 13485 | Melbourne, FL | MillingTurningSwissLaser | ISO 9001, ISO 13485 |
| Kiski Precision Industries, LLC Milling, Turning, Welding, Assembly | Leechburg, PA | MillingTurningWeldingAssembly | - |
| Kocsis Brothers Machine Company Welding, Assembly | Alsip, IL | WeldingAssembly | - |
| KP Manufacturing Milling, Casting, Finishing, Assembly | Spencer, IA | MillingCastingFinishingAssembly | - |
| Krametech, Inc Milling, Finishing, Assembly | Lake Zurich, IL | MillingFinishingAssembly | - |
| Krukemeier Machine Milling, Turning, EDM · AS9100, NADCAP | Indianapolis, IN | MillingTurningEDM | AS9100, NADCAP |
| Kyron Tool & Machine Co., Inc Milling, Turning, Welding | Columbus, OH | MillingTurningWelding | - |
| L.F. Industries, Inc Milling · ISO 9001, AS9100 | Carlsbad, CA | Milling | ISO 9001, AS9100 |
| La Follette Machine & Tool Company, Inc Laser, Bending · ISO 9001 | La Follette, TN | LaserBending | ISO 9001 |
| Lakes Area Manufacturing Co Milling, Grinding | Shafer, MN | MillingGrinding | - |
| Lakeview Forge Co Forging · ITAR | Erie, PA | Forging | ITAR |
| Lark Industries Turning, Waterjet, Welding, Assembly · ISO 9001, ISO 13485 | El Paso, TX | TurningWaterjetWeldingAssembly | ISO 9001, ISO 13485 |
| Laser Precision Cutting Inc Laser, Waterjet, Bending, Welding, Finishing | Weaverville, NC | LaserWaterjetBendingWeldingFinishing | - |
| Laserbend, LLC Laser, Bending, Welding, Finishing | Tujunga, CA | LaserBendingWeldingFinishing | - |
| Leanwerks, LLC Milling, Turning, Welding, Casting, Grinding, Assembly · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningWeldingCastingGrindingAssembly | ISO 9001, AS9100, ITAR, CMMC |
| Lee Precision Machine Shop Inc. Milling, Turning, Bending, Welding, EDM · ISO 9001, ITAR | Athens, AL | MillingTurningBendingWeldingEDM | ISO 9001, ITAR |
| Legacy Industries Laser, Welding, Stamping · ITAR | Auburn Hills, MI | LaserWeldingStamping | ITAR |
| Lehi Sheet Metal Turning, Laser, Punching, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100, ITAR | Westborough, MA | TurningLaserPunchingBendingWeldingGrindingFinishing | ISO 9001, AS9100, ITAR |