What is the proper procedure for tapping under power on a vertical milling machine?

Tapping under power on a vertical milling machine typically involves using low RPM settings and leaving the quill unlocked, allowing for greater control and maneuverability. This method helps to prevent the tap from breaking due to excessive force or misalignment. The ability to use both forward and reverse motions is crucial because forward motion engages the tap into the material, while reversing it helps in disengaging the tap safely after the desired depth is reached. This two-directional capability is essential for a successful and safe tapping process.

Using high RPM can lead to overheating and damaging the tap, while locking the quill may restrict movement and affect the precision of the tap's alignment. Moreover, while cutting fluid is beneficial for cooling and lubrication, it is not strictly necessary in all tapping situations, especially when considering tapping under power with proper technique. Therefore, the method that combines low RPM and both forward and reverse motions while leaving the quill unlocked is most effective for ensuring the tapping process concludes successfully.