counterbore

n.

（用平底扩孔钻）扩孔[锪孔，镗孔，镗阶梯孔]，沉孔，埋头孔；扩孔钻；

Counterbore dielectric plasma etch process particularly useful for dual damascene
Managing digital libraries for computer-aided design
Coaxial butt contact connector
Fluid actuated clamp
Method and apparatus for separating blood fractions
PLASTIC CONTAINER AND CLOSURE
Electrosurgical instrument
Lubricant fitting coupler with wedged lock ring
Earth boring drill
Medullary space drill