Coach builder's sliding bevel.

The sliding bevel is a valuable tool for measuring, checking and laying out angles when carrying out woodwork. The blade can be adjusted and held in position by the thumbscrew, allowing it to be matched to the relative positions of pieces of timber, or even the lines on large-scale drawings, and then used to duplicate the positions accurately. The bevel was a standard part of the toolkit for any tradesman working with wood, one of whom was the coach builder.