"镗孔工作" can be translated into English as "boring work" or more specifically as "boring operation" in the context of machining or manufacturing.
"Boring" here refers to the machining process of enlarging an existing hole with a single-point cutting tool, which is exactly what "镗孔" means in Chinese.
"Work" or "operation" can be used to describe the activity or task of performing this machining process.
In a professional or technical context, "boring operation" would be a more precise and commonly used term.