| HR Machine Turning, Waterjet, EDM | Dayton, OH | TurningWaterjetEDM | - |
| Icon Machine Co Milling, Turning, Casting · ISO 9001, AS9100 | Irving, TX | MillingTurningCasting | ISO 9001, AS9100 |
| 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 |
| Industrial Fabricators Milling, Turning, Bending, Welding, Waterjet | Corpus Christi, TX | MillingTurningBendingWeldingWaterjet | - |
| Industrial Sales & Manufacturing, Inc. Milling, Turning, Bending, Laser, Welding · ISO 9001 | Erie, PA | MillingTurningBendingLaserWelding | ISO 9001 |
| Infinity Precision Machining LLC Milling, Turning | Buffalo, NY | MillingTurning | - |
| Inno Tech Manufacturing Inc Milling, Turning, Laser · AS9100 | San Diego, CA | MillingTurningLaser | AS9100 |
| Innovated Metal Fabrication, Inc Turning, Bending, Laser, Welding | Maplewood, MN | TurningBendingLaserWelding | - |
| Innovation Alley Milling, Turning, Bending, Welding | Fresno, CA | MillingTurningBendingWelding | - |
| IPMI Manufacturing & Engineering Milling, Turning, Welding | Buckner, MO | MillingTurningWelding | - |
| Jaguar Precision Machine, LLC. Milling, Turning, Bending, Welding, Waterjet, Stamping, Metal AM · ISO 9001, AS9100, ITAR | Albuquerque, NM | MillingTurningBendingWeldingWaterjetStampingMetal AM | ISO 9001, AS9100, ITAR |
| Jax Precision Milling, Turning, Bending, Metal AM · ISO 9001, AS9100, ITAR | Jacksonville, FL | MillingTurningBendingMetal AM | ISO 9001, AS9100, ITAR |
| JD Machine Milling, Turning, Bending, Welding, EDM · ISO 9001, AS9100, ITAR, CMMC | Ogden, UT | MillingTurningBendingWeldingEDM | ISO 9001, AS9100, ITAR, CMMC |
| Jewett Machine Milling, Turning, Welding · ISO 9001 | Richmond, VA | MillingTurningWelding | ISO 9001 |
| Just In Time Machine Corp Milling, Turning, Welding · AS9100, ITAR | Middleton, WI | MillingTurningWelding | AS9100, ITAR |
| JW Machine (Praesto Enterprises, LLC) Milling, Turning, Laser · ISO 9001, AS9100, ITAR | Orlando, FL | MillingTurningLaser | ISO 9001, AS9100, ITAR |
| K C Machine Milling, Turning, Waterjet · ISO 9001, AS9100 | Excelsior Springs, MO | MillingTurningWaterjet | ISO 9001, AS9100 |
| Kadon Precision Machining Turning · ISO 9001 | Rockford, IL | Turning | ISO 9001 |
| KCSP Machine LLC (formerly Kansas City Screw Products) Milling, Turning, Welding · ISO 9001, AS9100 | Kansas City, MO | MillingTurningWelding | ISO 9001, AS9100 |
| Kelley-Tron Machine Co Milling, Turning | Harrisburg, PA | MillingTurning | - |
| King Precision Solutions Milling, Turning, Welding, EDM · ISO 9001, ITAR | Erie, PA | MillingTurningWeldingEDM | ISO 9001, ITAR |
| Krukemeier Machine Milling, Turning, EDM · AS9100, NADCAP | Indianapolis, IN | MillingTurningEDM | AS9100, NADCAP |
| Kyron Tool & Machine Co., Inc Milling, Turning, Welding | Columbus, OH | MillingTurningWelding | - |
| L&M machining center Milling, Turning, Metal AM · AS9100, ITAR | Tucson, AZ | MillingTurningMetal AM | AS9100, ITAR |
| La Machine Shop, Inc. Milling, Turning, Bending · ISO 9001, AS9100 | Ham Lake, MN | MillingTurningBending | ISO 9001, AS9100 |
| Lamjen Inc Milling, Turning, Welding, Stamping, Casting · ISO 9001 | Erie, PA | MillingTurningWeldingStampingCasting | ISO 9001 |
| Lee Precision Machine Shop Inc. Milling, Turning, Bending, Welding, EDM · ISO 9001, ITAR | Athens, AL | MillingTurningBendingWeldingEDM | ISO 9001, ITAR |
| Logan Machine Co Milling, Turning, Bending, Welding | Akron, OH | MillingTurningBendingWelding | - |
| Lorraine Machine Inc Turning, Welding · ISO 9001 | Greenville, SC | TurningWelding | ISO 9001 |
| Love Machine Turning, Welding | Salt Lake City, UT | TurningWelding | - |
| LT CNC Machining Inc. Milling, Turning, Welding · AS9100 | San Diego, CA | MillingTurningWelding | AS9100 |
| Luna's Sheet Metal Inc Milling, Turning, Bending, Laser, Welding | Santa Clara, CA | MillingTurningBendingLaserWelding | - |
| Luso Machine NJ, LLC Milling, Turning, Welding, EDM · ISO 9001 | Newark, NJ | MillingTurningWeldingEDM | ISO 9001 |
| M & J Manufacturing, Inc. Milling, Turning, EDM | Portland, OR | MillingTurningEDM | - |
| Mac-Tech Turning, Bending, Laser, Welding | Milwaukee, WI | TurningBendingLaserWelding | - |
| Mach3 Machining Milling, Turning, Welding · ISO 9001 | Cuyahoga Falls, OH | MillingTurningWelding | ISO 9001 |
| Machine Specialties Co Milling, Turning | Fort Worth, TX | MillingTurning | - |
| Machine Time Inc Milling, Turning, Bending, Welding · ISO 9001, AS9100 | Nicholasville, KY | MillingTurningBendingWelding | ISO 9001, AS9100 |
| Machine Tool Services Turning, Bending, EDM | Spokane, WA | TurningBendingEDM | - |
| Machined Products Co Turning, Welding · ISO 9001 | Lancaster, PA | TurningWelding | ISO 9001 |
| Machining Concepts Inc Milling, Turning, Casting · AS9100, ISO 13485 | Erie, PA | MillingTurningCasting | AS9100, ISO 13485 |
| Machinist Group Corporation Milling, Turning, Waterjet · ISO 9001, ITAR | Reno, NV | MillingTurningWaterjet | ISO 9001, ITAR |
| Majestic Metals by Fathom Manufacturing Milling, Turning, Bending, Laser, Welding, Waterjet, EDM, Casting, Metal AM · ISO 9001, AS9100, ITAR, ISO 13485 | Denver, CO | MillingTurningBendingLaserWeldingWaterjetEDMCastingMetal AM | ISO 9001, AS9100, ITAR, ISO 13485 |
| Major Tool & Machine Milling, Turning, Welding · ISO 9001, AS9100, NADCAP | Indianapolis, IN | MillingTurningWelding | ISO 9001, AS9100, NADCAP |
| Manda Machine Co Milling, Turning, Laser, Welding, Waterjet, EDM · ISO 9001, AS9100 | Dallas, TX | MillingTurningLaserWeldingWaterjetEDM | ISO 9001, AS9100 |
| Mark One Metal Works Turning, Bending, Welding | Sparks, NV | TurningBendingWelding | - |
| Master Machine, Inc Milling, Turning, Bending, Casting · ISO 9001 | Minneapolis, MN | MillingTurningBendingCasting | ISO 9001 |
| Mat-Tech Machining Milling, Turning, Welding | Milwaukee, WI | MillingTurningWelding | - |
| Maumee Valley Fabricators Turning, Welding | Toledo, OH | TurningWelding | - |