Most of the time, 461 uses English measurements in buying parts and all that good stuff. In 2004, though, with weight problems, we switched from 1" extrusion to 20mm extrusion with metric bolts and T-nuts. As far as design of the robot goes, most people use the english system (foot-pounds, etc...), but I use metric, for the simple reason that the metric system has the Watt
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