You don't always have to put the 0 on the m5 or m3 command, it will confuse some machines (trust me, confused machines aren't fun to be around). and i don't know why you'd want to reverse the spindle on a mill because the bit won't cut backwards. You only might use that once in a blue moon on cnc lathes, but never on mill unless your making reverse threads. And the spindle speed can be manually controlled on most machines using a knob in the back, you have to be carefull of the spindle speed, to fast and you could snap the bit, too slow and you'll either bind up the bit or make an extremely sloppy cut, and noone likes sloppy cuts
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Whats the difference between mechanical engineers and civil engineers?
Mechanical engineers build weapons, civil engineers build targets
