| Olympus Foundry Welding, Casting · AS9100, NADCAP | Millcreek, UT | WeldingCasting | AS9100, NADCAP |
| Omega Tool & Machine Casting · ISO 9001 | Battle Creek, MI | Casting | ISO 9001 |
| OMS Precision Machining Milling, Turning, Swiss, Casting, Grinding, Finishing · ISO 9001, ITAR | Oshkosh, WI | MillingTurningSwissCastingGrindingFinishing | ISO 9001, ITAR |
| Onamac Industries, Inc Milling, Turning, Casting, Grinding · ISO 9001, AS9100 | Everett, WA | MillingTurningCastingGrinding | ISO 9001, AS9100 |
| Owens Industries, Inc. Milling, Turning, Welding, EDM, Casting, Metal AM · ISO 9001, AS9100 | Oak Creek, WI | MillingTurningWeldingEDMCastingMetal AM | ISO 9001, AS9100 |
| Package One Industries, LLC Milling, Swiss, Waterjet, Bending, Welding, Stamping, Casting, Finishing, Assembly · ISO 9001, ITAR, NADCAP | Schenectady, NY | MillingSwissWaterjetBendingWeldingStampingCastingFinishingAssembly | ISO 9001, ITAR, NADCAP |
| Paragon D & E Milling, Bending, Casting · ISO 9001, AS9100, ITAR, CMMC | Grand Rapids, MI | MillingBendingCasting | ISO 9001, AS9100, ITAR, CMMC |
| Pioneer Products, Inc Milling, Turning, Casting, Grinding, Finishing, Assembly | Racine, WI | MillingTurningCastingGrindingFinishingAssembly | - |
| Plasidyne Engineering & Manufacturing Milling, Turning · ISO 9001, AS9100, ITAR | Long Beach, CA | MillingTurning | ISO 9001, AS9100, ITAR |
| Pme of Ohio, Inc Welding, Casting, Grinding | Minden, NV | WeldingCastingGrinding | - |
| Polyhistor International, Inc. Bending, Laser, Welding, Casting, Metal AM | Jacksonville, FL | BendingLaserWeldingCastingMetal AM | - |
| Porter Machine Inc Milling, Casting, Grinding · ISO 9001, AS9100 | West Greenwich, RI | MillingCastingGrinding | ISO 9001, AS9100 |
| Pre-Mach Inc Milling, Welding, Grinding, Finishing | York, PA | MillingWeldingGrindingFinishing | - |
| Precise Cast Prototypes & Engineering Inc Milling, Casting | Commerce City, CO | MillingCasting | - |
| Precision Components & Assemblies, Inc Milling, Turning, Laser, Welding, Casting, Finishing, Assembly | Saint Peters, MO | MillingTurningLaserWeldingCastingFinishingAssembly | - |
| Precision Manufacturing Group Inc Milling, Laser, Bending, Welding | Muskegon, MI | MillingLaserBendingWelding | - |
| Princeton Tool Inc Milling, Waterjet, Casting, EDM, Grinding, Assembly · AS9100, NADCAP | Mentor, OH | MillingWaterjetCastingEDMGrindingAssembly | AS9100, NADCAP |
| Prismier, LLC Stamping, Casting · ISO 9001 | Bolingbrook, IL | StampingCasting | ISO 9001 |
| Product Manufacturing Milling, Turning, Welding, Casting | Canby, OR | MillingTurningWeldingCasting | - |
| Production Pattern and Foundry Co Inc Milling, Turning, Casting, Finishing · ISO 9001, IATF 16949 | Mound House, NV | MillingTurningCastingFinishing | ISO 9001, IATF 16949 |
| Pronto Manufacturing Milling, Turning, EDM, Stamping | Ronkonkoma, NY | MillingTurningEDMStamping | - |
| Prosource Trace-A-Matic LLC Milling, Turning, Welding, Casting, EDM, Grinding, Assembly · ISO 9001, AS9100, ITAR | Brookfield, WI | MillingTurningWeldingCastingEDMGrindingAssembly | ISO 9001, AS9100, ITAR |
| Proto Edge, Inc Milling, Swiss, Casting, EDM, Assembly · ISO 9001 | Maple Grove, MN | MillingSwissCastingEDMAssembly | ISO 9001 |
| Prototek Milling, Turning, Bending, Laser, Welding, Waterjet, EDM, Casting, Metal AM · ISO 9001, AS9100, ITAR, CMMC | Rancho Cordova, CA | MillingTurningBendingLaserWeldingWaterjetEDMCastingMetal AM | ISO 9001, AS9100, ITAR, CMMC |
| Prototype Casting Inc Milling, Turning, Welding, Casting | Commerce City, CO | MillingTurningWeldingCasting | - |
| PT Coupling Milling, Turning, Welding, Casting, Grinding, Finishing · ISO 9001 | Enid, OK | MillingTurningWeldingCastingGrindingFinishing | ISO 9001 |
| QSR Steel Corporation Welding | Hartford, CT | Welding | - |
| Quality Castings Co Casting, Grinding · ISO 9001 | Orrville, OH | CastingGrinding | ISO 9001 |
| R & R Manufacturing Milling, Turning, Welding, Waterjet | Hillsboro, OR | MillingTurningWeldingWaterjet | - |
| R. J. Zeman Tool & Mfg. Co., Inc Milling, Turning, Welding, Casting, EDM, Grinding · ISO 9001, ITAR | Waukesha, WI | MillingTurningWeldingCastingEDMGrinding | ISO 9001, ITAR |
| Radian Thermal Products, Inc Milling, Casting, Finishing · ISO 9001, ITAR | Santa Clara, CA | MillingCastingFinishing | ISO 9001, ITAR |
| Ram Tool Inc Milling, Turning, Welding, Casting, EDM, Grinding · ISO 9001, ITAR | Grafton, WI | MillingTurningWeldingCastingEDMGrinding | ISO 9001, ITAR |
| RC Industries Milling · ISO 9001, AS9100 | Anaheim, CA | Milling | ISO 9001, AS9100 |
| Redstone Manufacturing USA Milling, Bending, Laser, Welding, Stamping, Casting · ISO 9001, AS9100, IATF 16949 | Seattle, WA | MillingBendingLaserWeldingStampingCasting | ISO 9001, AS9100, IATF 16949 |
| Retro Custom Metals Welding | Salt Lake City, UT | Welding | - |
| Revolution CNC LLC Milling, Turning, Welding | Hackettstown, NJ | MillingTurningWelding | - |
| Rice Precision Manufacturing Inc Milling, Turning, Swiss, Laser, Waterjet, Welding, Finishing, Assembly · ISO 9001, AS9100 | Baldwin City, KS | MillingTurningSwissLaserWaterjetWeldingFinishingAssembly | ISO 9001, AS9100 |
| S R Machining, Inc Milling, Turning, Swiss, Welding, Casting · ISO 9001, AS9100 | Norco, CA | MillingTurningSwissWeldingCasting | ISO 9001, AS9100 |
| San Jose Die Casting & Machining Corp Casting | Lincoln, CA | Casting | - |
| Seattle Makers Laser, Welding, Metal AM | Seattle, WA | LaserWeldingMetal AM | - |
| Sharp Tooling Company Milling, Turning, Bending, Welding, Waterjet, EDM, Stamping, Metal AM | Buffalo, NY | MillingTurningBendingWeldingWaterjetEDMStampingMetal AM | - |
| Silicon Valley Precision Inc Milling, Turning, Welding, Casting, Grinding, Finishing · ITAR | Livermore, CA | MillingTurningWeldingCastingGrindingFinishing | ITAR |
| Smith & Richardson Manufacturing Co Milling, Stamping, Casting | Geneva, IL | MillingStampingCasting | - |
| SMT Machine & Tool Milling, Turning, Welding, Casting | Green Bay, WI | MillingTurningWeldingCasting | - |
| Solidiform, Inc Milling, Casting, Finishing | Fort Worth, TX | MillingCastingFinishing | - |
| Sonic Manufacturing Corporation Milling, Welding, EDM, Grinding, Finishing, Assembly · AS9100, NADCAP | Elk Grove Village, IL | MillingWeldingEDMGrindingFinishingAssembly | AS9100, NADCAP |
| Southern Metal Fabricators, Inc Welding, Casting | Albertville, AL | WeldingCasting | - |
| Specialty Roller and Machine Inc Milling, Turning, Grinding | Berwick, PA | MillingTurningGrinding | - |
| Spintek Foundry and Machine LLC Milling, Casting | Mound House, NV | MillingCasting | - |
| Spuncast Inc Casting · ISO 9001 | Watertown, WI | Casting | ISO 9001 |