| 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 |
| Just In Time Machine Corp Milling, Turning, Welding · AS9100, ITAR | Middleton, WI | MillingTurningWelding | AS9100, ITAR |
| K&M Milling, Turning, Laser, Welding, Assembly · ISO 9001 | Cassopolis, MI | MillingTurningLaserWeldingAssembly | ISO 9001 |
| Kammerer Dynamics Inc Laser, Bending, Welding, Casting, Finishing, Assembly | Kendallville, IN | LaserBendingWeldingCastingFinishingAssembly | - |
| Kamprecision Fabrication LLC Welding | Scottsburg, IN | Welding | - |
| KB Sheetmetal Fabrication, Inc Turning, Bending, Welding, Finishing · ISO 9001 | Fountain Valley, CA | TurningBendingWeldingFinishing | ISO 9001 |
| Kencoa Aerospace LLC Milling, Turning, Waterjet, Punching, Bending, Welding, Stamping · AS9100, ITAR | Eastman, GA | MillingTurningWaterjetPunchingBendingWeldingStamping | AS9100, ITAR |
| Kern Steel Fabrication Inc Bending, Welding · ISO 9001 | Bakersfield, CA | BendingWelding | ISO 9001 |
| 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 | - |
| Kirsh Manufacturing Inc Milling, Turning, Welding, Grinding, Finishing · ISO 9001, ITAR | Tucson, AZ | MillingTurningWeldingGrindingFinishing | ISO 9001, ITAR |
| Kocsis Brothers Machine Company Welding, Assembly | Alsip, IL | WeldingAssembly | - |
| Korzan Enterprises Inc Milling, Turning, Waterjet, Welding, EDM, Grinding, Finishing | Orchard Park, NY | MillingTurningWaterjetWeldingEDMGrindingFinishing | - |
| Kozel Steel Welding | Rochester, NY | Welding | - |
| Kriewall Enterprises Inc Milling, Laser, Welding, Stamping, EDM, Finishing · ISO 9001 | Romeo, MI | MillingLaserWeldingStampingEDMFinishing | ISO 9001 |
| Kte Holdings LLC Milling, Turning, Welding, Grinding, Finishing | Mableton, GA | MillingTurningWeldingGrindingFinishing | - |
| L. C. S. Co Laser, Welding, Stamping, EDM · ISO 9001, AS9100, ITAR, NADCAP | Saint Paul, MN | LaserWeldingStampingEDM | ISO 9001, AS9100, ITAR, NADCAP |
| L. E. F., Inc Milling, Laser, Bending, Welding, Stamping, Finishing | Tulsa, OK | MillingLaserBendingWeldingStampingFinishing | - |
| L.a. Martin Company Milling, Turning, Bending, Welding, Grinding, Finishing · ISO 9001 | Dearborn, MI | MillingTurningBendingWeldingGrindingFinishing | ISO 9001 |
| L&B Labs Milling, Turning, Laser, Welding, EDM, Grinding | San Jose, CA | MillingTurningLaserWeldingEDMGrinding | - |
| Lai International Inc Milling, Laser, Waterjet, Welding, Metal AM, EDM, Finishing · NADCAP | Westminster, MD | MillingLaserWaterjetWeldingMetal AMEDMFinishing | NADCAP |
| Langill's General Machine Inc Milling, Welding | Sacramento, CA | MillingWelding | - |
| Lasasco Inc Punching, Bending, Welding | Boise, ID | PunchingBendingWelding | - |
| Laser Precision Cutting Inc Laser, Waterjet, Bending, Welding, Finishing | Weaverville, NC | LaserWaterjetBendingWeldingFinishing | - |
| Laserbend, LLC Laser, Bending, Welding, Finishing | Tujunga, CA | LaserBendingWeldingFinishing | - |
| Laserform & Machine Inc Turning, Laser, Punching, Bending, Welding, Finishing, Assembly · ISO 9001 | Columbia, SC | TurningLaserPunchingBendingWeldingFinishingAssembly | ISO 9001 |
| Lawrence Fabric & Metal Structures, Inc. Welding · ISO 9001 | St. Louis, MO | Welding | ISO 9001 |
| Lawruk Machine & Tool Milling, Turning, Welding, Grinding · ISO 9001 | Altoona, PA | MillingTurningWeldingGrinding | ISO 9001 |
| Lawson Precision Machining, Inc Milling, Turning, Welding, Grinding · ISO 9001 | Bucyrus, OH | MillingTurningWeldingGrinding | ISO 9001 |
| Laystrom Manufacturing Company Bending, Laser, Welding | Chicago, IL | BendingLaserWelding | - |
| LD Redmer Milling, Turning, Swiss, Welding, Finishing · ISO 9001, ITAR, NADCAP | Bensenville, IL | MillingTurningSwissWeldingFinishing | ISO 9001, ITAR, NADCAP |
| 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 |
| Lewis Precision & CNC Inc Milling, Turning, Bending, Welding, Grinding, Finishing · ISO 9001, AS9100 | Theodore, AL | MillingTurningBendingWeldingGrindingFinishing | ISO 9001, AS9100 |
| LG Metalworks LLC Milling, Turning, Laser, Waterjet, Welding, EDM, Finishing | Bloomington, IN | MillingTurningLaserWaterjetWeldingEDMFinishing | - |
| Lima Sheet Metal Machine and Mfg., Inc Turning, Bending, Welding, Grinding | Lima, OH | TurningBendingWeldingGrinding | - |
| Lindor Tool, Inc Milling, Turning, Welding, Casting, Grinding | Saint Croix Falls, WI | MillingTurningWeldingCastingGrinding | - |
| LJ Fabricators, Inc. Bending, Laser, Welding · ISO 9001 | Rockford, IL | BendingLaserWelding | ISO 9001 |
| LNP Machining Milling, Turning, Welding, Finishing · ISO 9001, AS9100, ITAR, ISO 13485 | San Jose, CA | MillingTurningWeldingFinishing | ISO 9001, AS9100, ITAR, ISO 13485 |
| Lodolce Machine Co, Inc Milling, Turning, Laser, Welding, EDM, Assembly · ISO 9001, AS9100 | Saugerties, NY | MillingTurningLaserWeldingEDMAssembly | ISO 9001, AS9100 |
| Lorraine Machine Inc Turning, Welding · ISO 9001 | Greenville, SC | TurningWelding | ISO 9001 |
| Luna's Sheet Metal Inc Milling, Turning, Bending, Laser, Welding | Santa Clara, CA | MillingTurningBendingLaserWelding | - |
| Lunsford Manufacturing and Sheet Metal LLC Welding | Grand Junction, CO | Welding | - |
| LX3 Tooling Milling, Turning, Laser, Welding, Grinding · CMMC | Aledo, TX | MillingTurningLaserWeldingGrinding | CMMC |
| Lynchburg Machining, LLC Milling, Turning, Waterjet, Bending, Welding, EDM · ISO 9001 | Lynchburg, VA | MillingTurningWaterjetBendingWeldingEDM | ISO 9001 |
| M & M Sheet Metal, Inc Milling, Laser, Bending, Welding, Forging · ISO 9001, ITAR, CMMC | Williamsport, PA | MillingLaserBendingWeldingForging | ISO 9001, ITAR, CMMC |
| M & S Machining Inc Milling, Turning, Bending, Welding, EDM, Assembly · ISO 9001, AS9100, ITAR | Winchester, KY | MillingTurningBendingWeldingEDMAssembly | ISO 9001, AS9100, ITAR |
| M 7 Technologies Bending, Welding · ISO 9001 | Youngstown, OH | BendingWelding | ISO 9001 |
| M W M Services, Inc Milling, Welding, EDM | Riviera Beach, FL | MillingWeldingEDM | - |