U.S. machine tool orders surged 85.6% during the first nine months of the year over the same 1987 period, the National Machine Tool Builders Assn. reported. The trade group said that for the first nine months of 1988, new orders totaled $2.7 billion, up from $1.5 billion a year ago. It said orders for September were down 3.4% from August but were 79.3% above their year-ago level. So far this year, machine tool shipments have totaled $1.6 billion, about the same as in the comparable 1987 period. Shipments rose 47.5% in September from August, and the machine tool backlog for September stood at $2.1 billion, up from $2 billion in August.