Where is the gage line located on a CNC mill?

Where is the gage line located on a CNC mill?

• A. Above the flange
• B. Below the bed
• C. On the spindle
• D. At the tailstock

Answer: (A)

The gage line is a reference line used for setting up and checking measurements with gauges or gauging devices. On a CNC mill, placing that reference line above the spindle flange makes it easily accessible and unobstructed by the machine bed or tailstock. This position keeps gauging operations aligned with the front of the spindle where tools and workpieces are held, allowing reliable checks of diameter, runout, or alignment against a known datum. Putting the line below the bed would be blocked by the machine structure, while placing it directly on the spindle or at the tailstock isn’t practical for consistent gauging during milling operations.

The gage line is a reference line used for setting up and checking measurements with gauges or gauging devices. On a CNC mill, placing that reference line above the spindle flange makes it easily accessible and unobstructed by the machine bed or tailstock. This position keeps gauging operations aligned with the front of the spindle where tools and workpieces are held, allowing reliable checks of diameter, runout, or alignment against a known datum. Putting the line below the bed would be blocked by the machine structure, while placing it directly on the spindle or at the tailstock isn’t practical for consistent gauging during milling operations.