The plan of a quarter-turn winding stairway, with a quarter cylinder for a continued hand rail, and with regular treads above and below, is shown in Fig. 41. It will be noticed that the treads adjoining the cylinder in both flights are reduced. The benefit derived from the reduction will appear in the curve of the rail and stringer, as it modifies the angle of intersection between the pitch of one straight rail and that over the winders, the stringer, of course, being affected in the same manner.

45 Quarter Turn Winding 59

Fig. 41.