| Kinney Manufacturing, LLC Bending, Laser, Welding, Metal AM | Lincoln, NE | BendingLaserWeldingMetal AM | - |
| Kinross Fab & Machine Inc Milling, Turning, Laser, Welding, Grinding, Finishing | Kincheloe, MI | MillingTurningLaserWeldingGrindingFinishing | - |
| KLW Manufacturing & Design, Inc Milling, Assembly | Arlington, WA | MillingAssembly | - |
| Ko Laser Milling, Turning, Laser, Bending, Welding | Tulsa, OK | MillingTurningLaserBendingWelding | - |
| Kocsis Brothers Machine Company Welding, Assembly | Alsip, IL | WeldingAssembly | - |
| Kozel Steel Welding | Rochester, NY | Welding | - |
| Krametech, Inc Milling, Finishing, Assembly | Lake Zurich, IL | MillingFinishingAssembly | - |
| Kriewall Enterprises Inc Milling, Laser, Welding, Stamping, EDM, Finishing · ISO 9001 | Romeo, MI | MillingLaserWeldingStampingEDMFinishing | ISO 9001 |
| Krisalis Precision Machining Milling, Turning | San Andreas, CA | MillingTurning | - |
| KSM Industries Inc Bending, Welding, Assembly | Germantown, WI | BendingWeldingAssembly | - |
| L C Metals Inc Stamping | Austell, GA | Stamping | - |
| L-E-M Plastics & Supply, Inc Milling, Punching, Welding · AS9100 | Fairfield, NJ | MillingPunchingWelding | AS9100 |
| L. E. F., Inc Milling, Laser, Bending, Welding, Stamping, Finishing | Tulsa, OK | MillingLaserBendingWeldingStampingFinishing | - |
| Laciny Brothers., Inc. Bending, Welding, Waterjet | St. Louis, MO | BendingWeldingWaterjet | - |
| Lacross Enterprises Inc Turning, Laser, Punching, Bending, Welding | Louisville, KY | TurningLaserPunchingBendingWelding | - |
| Lai International Inc Milling, Laser, Waterjet, Welding, Metal AM, EDM, Finishing · NADCAP | Westminster, MD | MillingLaserWaterjetWeldingMetal AMEDMFinishing | NADCAP |
| Lake Precision Machine Inc Turning, Welding | Hagerstown, MD | TurningWelding | - |
| Lakecity Industries Holding Inc Finishing | Lake City, PA | Finishing | - |
| Lancaster Design & Machine Milling, Welding, Grinding · ISO 9001 | Dacula, GA | MillingWeldingGrinding | ISO 9001 |
| Langdon Inc Welding | Cincinnati, OH | Welding | - |
| Langley Industrial Machining Milling, Turning, Laser, Punching, Welding, Stamping, Finishing · ISO 9001 | Sharpsburg, NC | MillingTurningLaserPunchingWeldingStampingFinishing | ISO 9001 |
| Lanzen Inc Milling, Laser, Welding | Bruce Twp, MI | MillingLaserWelding | - |
| Lasasco Inc Punching, Bending, Welding | Boise, ID | PunchingBendingWelding | - |
| Laser Craft Technologies Inc Milling, Turning, Laser, Punching, Bending, Welding, Assembly · ISO 9001 | Gainesville, GA | MillingTurningLaserPunchingBendingWeldingAssembly | ISO 9001 |
| Laser Cutting Co Milling, Laser, Bending, Welding, Grinding, Finishing · ISO 9001 | Harrison Township, MI | MillingLaserBendingWeldingGrindingFinishing | ISO 9001 |
| Laserworx Mfg Laser, Bending, Welding, Stamping · AS9100, ITAR | Oxnard, CA | LaserBendingWeldingStamping | AS9100, ITAR |
| Latitude Corp Milling, Waterjet, Punching, Bending, Welding, Stamping, Grinding, Finishing · AS9100 | Verona, WI | MillingWaterjetPunchingBendingWeldingStampingGrindingFinishing | AS9100 |
| Lawrence Fabric & Metal Structures, Inc. Welding · ISO 9001 | St. Louis, MO | Welding | ISO 9001 |
| Layne West Manufacturing LLC Milling, Swiss, Welding, Grinding | Boise, ID | MillingSwissWeldingGrinding | - |
| Laystrom Manufacturing Company Bending, Laser, Welding | Chicago, IL | BendingLaserWelding | - |
| Leading Edge Manufacturing, L.L.C Welding, Finishing | Youngsville, LA | WeldingFinishing | - |
| Lear Machining & Waterjet Inc Milling, Turning, Waterjet, Welding, Grinding · ISO 9001 | Columbus, IN | MillingTurningWaterjetWeldingGrinding | ISO 9001 |
| Lee Precision Machine Shop Inc. Milling, Turning, Bending, Welding, EDM · ISO 9001, ITAR | Athens, AL | MillingTurningBendingWeldingEDM | ISO 9001, ITAR |
| Legion Metals Welding | Oklahoma City, OK | Welding | - |
| Lehi Sheet Metal Turning, Laser, Punching, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100, ITAR | Westborough, MA | TurningLaserPunchingBendingWeldingGrindingFinishing | ISO 9001, AS9100, ITAR |
| Lemmatic Precision LLC Milling, Turning, Finishing · ISO 9001, ITAR | American Fork, UT | MillingTurningFinishing | ISO 9001, ITAR |
| Lewis Precision & CNC Inc Milling, Turning, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100 | Theodore, AL | MillingTurningBendingWeldingGrindingFinishing | ISO 9001, AS9100 |
| Lima Sheet Metal Machine and Mfg., Inc Turning, Bending, Welding, Grinding | Lima, OH | TurningBendingWeldingGrinding | - |
| Limestone Manufacturing LLC Milling, Turning, Laser, Bending, Welding, Metal AM, EDM, Grinding · ISO 9001, AS9100 | Somerset, KY | MillingTurningLaserBendingWeldingMetal AMEDMGrinding | ISO 9001, AS9100 |
| Lindquist Machine Co., LLC Welding · ISO 9001 | Green Bay, WI | Welding | ISO 9001 |
| Lindsay Machine Works, Inc Milling, Turning, Laser, Waterjet, Bending, Welding, Grinding | Independence, MO | MillingTurningLaserWaterjetBendingWeldingGrinding | - |
| LM Gill Welding & Manufacturing LLC Milling, Welding · ISO 9001, AS9100, ITAR, NADCAP | Manchester, CT | MillingWelding | ISO 9001, AS9100, ITAR, NADCAP |
| Lockrey Manufacturing Welding, Finishing · ISO 9001, ITAR | Toledo, OH | WeldingFinishing | ISO 9001, ITAR |
| Lodolce Machine Co, Inc Milling, Turning, Laser, Welding, EDM, Assembly · ISO 9001, AS9100 | Saugerties, NY | MillingTurningLaserWeldingEDMAssembly | ISO 9001, AS9100 |
| Logan Machine Co Milling, Turning, Bending, Welding | Akron, OH | MillingTurningBendingWelding | - |
| Loughmiller Machine, Tool & Design Milling, Turning, Waterjet, Welding, EDM, Finishing | Loogootee, IN | MillingTurningWaterjetWeldingEDMFinishing | - |
| Loutech LLC Milling, Turning, Swiss, Finishing · ISO 9001, AS9100, ITAR | Chino, CA | MillingTurningSwissFinishing | ISO 9001, AS9100, ITAR |
| Lovejoy Chaplet Corp Milling, Turning, Swiss | Hoosick Falls, NY | MillingTurningSwiss | - |
| LR Design+Build Laser, Welding, Metal AM | Columbus, OH | LaserWeldingMetal AM | - |
| M & M Sheet Metal, Inc Milling, Laser, Bending, Welding, Forging · ISO 9001, ITAR, CMMC | Williamsport, PA | MillingLaserBendingWeldingForging | ISO 9001, ITAR, CMMC |