The most basic use for a combination square in your shop will be marking out square cuts along the rule edge.
You won't find a more versatile or accurate tool for layout.
In turning, a combination square will help you find and mark out the center point of your stock for mounting it on the lathe.
The blade’s etched graduations allow precise measuring and marking.The head is designed to register reliably against an edge.
For longer markings set the combination square along one edge of the panel, and then drag it and the pencil along the length.
The adjustability of the head along the blade enhances the tool’s capabilities.