Let\'s take 4 table columns - ID, Text, Date, Action. In my case table have always constant width - in example 960px.
My best advice to you is to not touch the widths of the table, the table automatically layouts in a way that does all cells best.
However, if you'd like to push through, I'd use width: 1px; on the cells that needs adjusting (one of each column is enough). Also use white-space: nowrap on all cells. that will make sure the lines don't break.