Fig. 1 shows the plan of a stair starting with a scroll. Make D E equal about 4 times the width of rail, which divide into 9 equal parts; make D I equal 5 of these parts; this will be the radius for the largest quadrant of the rail. To find the radius for each of the remaining quadrants, make D 1, Fig. 5, equal D 1, Fig. 1; make 1 2 equal one of the 9 parts, with D as centre and D 1 as radius; strike an arc from 2; square up a line to cut the arc in A; join A D with D as centre and D 2 as radius; strike an arc to cut A D in B; from B draw B 3 square to D 1. Continue the process as far as required to complete the scroll, D 2 will strike the second quadrant and D 3 the third, and so on. The face mould is seen at Fig. 3. Draw C B A at right angles and make C B equal C B, Fig. 2, and A B equal A B, Fig. 1. Make A R equal radius of centre line of rail C 1, Fig. 1, and complete the mould as usual. The scroll itself will only require to be the thickness of the rail, as it is level. All the sections in the wreath will be in the centre of the plank.
Fig. 6 shows the plan, and Fig. 7 the elevation of a side wreath starting from a newel. Make A P, Fig. 8, equal the radius of centre line of rail, Fig. 6, and draw V L through P square to A P. Make A E equal A E, Fig. 6, draw E 8 square to A E, and make E 8 equal B D, Fig. 7. Join A 8 extended to cut V L in O; then O will be the centre and A O the major axis. Make A B and 8 C equal A B and E C, Fig. 6. Join C B, which is the tangent, and if the drawing is correct, this will equal C B, Fig. 7. The tangent A B being level is of course the same length as on plan. All the sections will be in the centre of the plank; these are seen at Fig. 9. The short shank A N is to let into the newel; A being the face of newel.