Straight Edge 
A tool used to determine, along with the use of a measure, the evenness of a surface. It might be a specially manufactured 3-m length of aluminium or an improvised tool, such as a large spirit level.
Straight Edge
A tool used to determine, along with the use of a measure, the evenness of a surface. It might be a specially manufactured 3-m length of aluminium or an improvised tool, such as a large spirit level.