Updated from 7:07 a.m. EDTMost industrial stocks have gotten killed lately, as investors fear a global slowdown will affect the sector's forward earnings power. But the time to buy industrial stocks is when their forward P/Es seem sky-high and their sales seem to be failing off a cliff. Conversely, the time to sell industrial stocks is when their forward P/Es seem extremely low and revenue is running at 110% of capacity. Some industrial stocks, such as Gardner Denver ( GDI), have gotten too cheap to ignore. To read more, visit Stockpickr.com.