2020-06-04 Update:
OOPs - I just noticed that I intended to post this chart, instead of a duplicate of what I had already posted.
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The cutting powers in that chart (column K) were calculated from the increase in motor current (torque) and spindle speed when cutting as shown on the left side of the spreadsheet segment shown below. The right spreadsheet segment shows pretty good correlation with power calculated from motor input current and motor voltage for the assumed power factor and motor efficiency (column R).
