The basic engine lathe, one of the most widely used machine tools, is very versatile when used by a skilled machinist. However, it is not particularly efficient when many identical parts must be machined as rapidly as possible. As far back as 1850 there were efforts to develop variations of an engine lathe that could be operated by a relatively unskilled person for mass-producing machined parts. The cutting tools were preset, or "set up" by a skilled machinist, and usually several cutting tools were in operation at the same time, reducing the time spent in machining each part. This is still the basic concept on which mass-production type lathes are based.