Question

when is the cutting speed to be adjusted on the vertical milling machine? 17. what direction does the cutting tool always have to be rotating in before we begin cutting?

Explanation:

Answer:

For the first question (about adjusting cutting speed on vertical milling machines): Cutting speed on vertical milling machines is adjusted when there is a change in the workpiece material, the type of cutting tool (e.g., material, diameter), or the depth/width of the cut to ensure optimal machining (like preventing tool wear, achieving desired surface finish, or efficient material removal).
For question 17: The cutting tool on a vertical milling machine ALWAYS has to be rotating in the correct cutting direction (typically clockwise when viewed from above the spindle for a vertical mill, following the direction that allows the tool to engage the workpiece for cutting, often the "downward" or "clockwise" rotation relative to the workpiece to perform the milling operation safely and effectively) before beginning cutting.

(Note: If a more concise answer for the rotation direction is needed, the standard is that the cutting tool rotates in the direction that provides the correct cutting action, usually clockwise for a vertical mill's spindle when looking down, to ensure the tool cuts into the workpiece properly; the exact phrasing might depend on machine setup, but the key is the correct cutting - oriented rotation (e.g., the direction that makes the tool teeth cut the workpiece, not just spin idly, so the "cutting direction" which is the direction that allows the tool to remove material, often clockwise in vertical mills for conventional or climb milling setups depending on the operation, but the core is that it must be rotating in the direction intended for the cutting process to start safely and effectively.))