Summary

The preparation of the work surface and laying out straight lines is the basic operation that is performed in the layout. As the accuracy of the finished work-piece depends on the accuracy of the layout, proper care should be taken throughout the process. The surface of the work should be coated along with a layout material so that scribed lines will be seen easily. The surface have to be clean and free from grease, dust, surface scale, oil etc. if not layout material will not stick on it. The straight lines are scribed along with the aid of scriber and combination square, surface plate and surface gauge, Vernier height gauge and surface plate.   Combination tool is utilized where accuracy is not important. Square head is used for laying out horizontal and parallel straight lines. Center holes are positioned by means of center head, hermaphrodite calipers, and surface gauge. The center head is utilized to lay out the center of round and square work-pieces.