| Blake Machine Milling, Turning, Welding | Phoenix, AZ | MillingTurningWelding | - |
| Blue Chip Machine Milling, Finishing, Assembly | Vassalboro, ME | MillingFinishingAssembly | - |
| Blue Waters Engineering LLC Milling · ISO 9001, AS9100, ITAR | Vancouver, WA | Milling | ISO 9001, AS9100, ITAR |
| Bluewater Industries Inc Milling, Turning, Welding, Casting, Finishing | Moses Lake, WA | MillingTurningWeldingCastingFinishing | - |
| BMW Precision Machining Milling, Turning, Swiss · ITAR | Oceanside, CA | MillingTurningSwiss | ITAR |
| Bob Lewis Machine Company, Inc Milling, Turning, Welding, EDM, Grinding, Finishing · ISO 9001, AS9100 | Gardena, CA | MillingTurningWeldingEDMGrindingFinishing | ISO 9001, AS9100 |
| Bogue Machine Co Inc Milling, Turning, Bending, Welding, Waterjet, EDM · ISO 9001, AS9100, ITAR | Albuquerque, NM | MillingTurningBendingWeldingWaterjetEDM | ISO 9001, AS9100, ITAR |
| Bollinger Atelier Milling, Waterjet, Welding, Casting | Tempe, AZ | MillingWaterjetWeldingCasting | - |
| Boniface Tool & Die Inc Milling, Turning, Waterjet, Stamping, Grinding, Finishing | Dudley, MA | MillingTurningWaterjetStampingGrindingFinishing | - |
| Bonneville Machine Milling, Turning, Welding · ISO 9001 | Salt Lake City, UT | MillingTurningWelding | ISO 9001 |
| Borg Design Inc Milling, Turning · ISO 9001, AS9100, ITAR, CMMC | Hudson, MA | MillingTurning | ISO 9001, AS9100, ITAR, CMMC |
| Boulevard Machine & Gear, Inc Milling, Turning, Grinding · ISO 9001, AS9100, ITAR | Westfield, MA | MillingTurningGrinding | ISO 9001, AS9100, ITAR |
| Bowden Manufacturing Corp Milling, Turning, EDM · AS9100 | Willoughby, OH | MillingTurningEDM | AS9100 |
| Boyce Machine Milling, Turning, Welding | Kent, OH | MillingTurningWelding | - |
| Boyer Machine & Tool Co Inc Milling, Turning, Swiss, EDM · ITAR | Columbus, IN | MillingTurningSwissEDM | ITAR |
| Bozeman CNC LLC Milling, Laser, Finishing · ISO 9001, AS9100, ITAR | Manhattan, MT | MillingLaserFinishing | ISO 9001, AS9100, ITAR |
| Brace Manufacturing Milling, Bending, Welding, Assembly | Garland, TX | MillingBendingWeldingAssembly | - |
| Brantley R Lingerfelt Milling, Turning, Finishing | Carnesville, GA | MillingTurningFinishing | - |
| Braun Co. Engineering LLC Milling, Turning, Swiss, Grinding | Signal Hill, CA | MillingTurningSwissGrinding | - |
| Breakout Manufacturing, LLC Milling, Finishing, Assembly · ITAR, CMMC | Murphy, TX | MillingFinishingAssembly | ITAR, CMMC |
| Brenk Brothers Inc Milling, Turning, EDM, Grinding | Minneapolis, MN | MillingTurningEDMGrinding | - |
| Brennan Machine Co., Inc Milling · ISO 9001 | Hanson, MA | Milling | ISO 9001 |
| Bridan Mfg Inc Milling, Turning, EDM · ISO 9001 | Kenosha, WI | MillingTurningEDM | ISO 9001 |
| Brinker Machine LLC Milling, Turning, Bending, Welding | Letart, WV | MillingTurningBendingWelding | - |
| Bristol Manufacturing LLC Milling, Turning, EDM · ITAR | Sealy, TX | MillingTurningEDM | ITAR |
| Brogan Acquisition Holdco LLC Milling, Turning, Grinding · ISO 9001 | Elkhorn, WI | MillingTurningGrinding | ISO 9001 |
| Bronco Manufacturing Inc Milling, Turning, Assembly · ISO 9001, ITAR | Anna, TX | MillingTurningAssembly | ISO 9001, ITAR |
| Bront Machining Inc. Milling, Turning, Welding · ISO 9001, AS9100 | Dayton, OH | MillingTurningWelding | ISO 9001, AS9100 |
| Brown Industries Inc Milling, Turning, Bending, Welding | Kansas City, MO | MillingTurningBendingWelding | - |
| Brown Precision Inc Milling, Turning, Bending, Welding, Waterjet, EDM · ISO 9001, AS9100 | Huntsville, AL | MillingTurningBendingWeldingWaterjetEDM | ISO 9001, AS9100 |
| Bryant Machine Co Inc Milling, Turning · ISO 9001, AS9100, ITAR | Jacksonville, AL | MillingTurning | ISO 9001, AS9100, ITAR |
| BS Designs Inc Milling, Turning, Welding | Santee, CA | MillingTurningWelding | - |
| BT Machine Inc Milling, Turning, Welding, Finishing · ISO 9001, AS9100, ITAR | Tulsa, OK | MillingTurningWeldingFinishing | ISO 9001, AS9100, ITAR |
| Buckingham Tool Corp Milling, Turning, Welding, Grinding | Livonia, MI | MillingTurningWeldingGrinding | - |
| Buddy Bar Casting, LLC Milling, Casting | South Gate, CA | MillingCasting | - |
| Bullet Fabrication LLC Milling, Bending, Welding | Gardena, CA | MillingBendingWelding | - |
| Burger & Brown Engineering Inc Milling, Turning, Swiss | Grandview, MO | MillingTurningSwiss | - |
| Burke Precision Machine Company, Incorporated Milling, Turning, Grinding · ISO 9001 | East Granby, CT | MillingTurningGrinding | ISO 9001 |
| Burnet Machining Inc Milling, Turning | Goleta, CA | MillingTurning | - |
| Burns Machine Co Milling, Turning, Bending, Welding, Grinding, Assembly · ISO 9001 | Ottawa, IL | MillingTurningBendingWeldingGrindingAssembly | ISO 9001 |
| Burton Industries Inc Milling, Turning, Stamping, Grinding · ISO 9001, AS9100, IATF 16949 | Mentor, OH | MillingTurningStampingGrinding | ISO 9001, AS9100, IATF 16949 |
| Butler Precision Technologies LLC Milling, Turning, Welding, Finishing · AS9100, ITAR | Bristol, PA | MillingTurningWeldingFinishing | AS9100, ITAR |
| Bvi Machining, Inc Milling | Houston, TX | Milling | - |
| Byers Precision Fabricators, Inc Milling, Laser, Bending, Welding · ISO 9001 | Hendersonville, NC | MillingLaserBendingWelding | ISO 9001 |
| C & C Machine Inc Milling, Turning, Bending, Welding | La Crosse, WI | MillingTurningBendingWelding | - |
| C & C Machining, Inc Milling, Turning, EDM, Grinding, Finishing | Hayward, CA | MillingTurningEDMGrindingFinishing | - |
| C & S Machine & Manufacturing Corp Milling, Turning, Laser, Bending, Welding · ISO 9001, AS9100 | Louisville, KY | MillingTurningLaserBendingWelding | ISO 9001, AS9100 |
| C & T Industrial Machine Shop, Inc Milling, Turning, Waterjet, Welding | Byron, GA | MillingTurningWaterjetWelding | - |
| C and C Machining LLC Milling, Turning, Assembly | Fort Worth, TX | MillingTurningAssembly | - |
| C M Engineering Inc Milling, Laser, Bending, Welding, Finishing, Assembly · ISO 9001 | Dugger, IN | MillingLaserBendingWeldingFinishingAssembly | ISO 9001 |