This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
When the treads and risers are supported by rough cut carriages, it becomes necessary to cut a wall stringer that will fit around the steps and make a finish with the wall. In Fig. 8 is shown a method of scribing a wall stringer. The stringer is represented as being laid with one edge on the line of the nosings, and the instrument to be used is shown in position. The hard-wood or iron bar b h has a hook on the lower end projecting sufficiently to enable the bar to clear the nosing when the point b is touching the face of the riser. The bar b h is placed against the guide m and loosely bound to it by the metal straps e and k. The strip n is fastened to m by a bolt a, which can be tightened so as to preserve the bevel. A small nick is made in the sliding bar b h at c, so that b c is the height of a riser. When the point b is on the end of the nosing, the nick c gives the position of the corresponding point on the wall stringer. Other points may be found in a similar manner, and the outline to which the wall stringer is to be cut can then be drawn.