Design the layout of a $12-$speed gear box for a milling machine having an output of speeds ranging from $180$ to $2000$ rpm$.$ Power is applied to the gear box from a $6-$kW induction motor at $1440$ rpm$.$ Choose standard step ratio and construct the speed diagram. Decide upon the various reduction ratios and number of teeth on each gear wheel sketch the arrangement of the gear box.$($please don't copy from chatgpt and give me those diagram perfectly asked in the above question$)$