Sixth Case. In this case we have one tangent inclining and one tangent level, over an acute-angle plan.
Fig. 119. Laying Out Curves on Face-Mould with Pins and String.
In [Fig. 115] is shown the same plan as in [Fig. 114]; but in this case the bottom tangent a″ is to be a level tangent. Probably this condition is the most commonly met with in wreath construction at the present time. A small curve is considered to add to the appearance of the stair and rail; and consequently it has become almost a “fad” to have a little curve or stretch-out at the bottom of the stairway, and in most cases the rail is ramped to intersect the newel at right angles instead of at the pitch of the flight. In such a case, the bottom tangent a″ will have to be a level tangent, as shown at a″ in [Fig. 115], the pitch of the flight being over the plan tangent b only.
To find the bevels when tangent b″ inclines and tangent a″ is level, make a c in [Fig. 116] equal to a c in [Fig. 115]. This line will be the base of the two bevels. Upon a, erect the line a w m at right angles to a c; make a w equal to o w in [Fig. 115]; connect w and c; the bevel at w will be the one to apply to tangent b″ at n where the wreath is joined to the rail of the flight. Again, make a m in [Fig. 116] equal the distance shown in [Fig. 115] between w and m, which is the full height over which tangent b″ is inclined; connect m to c in [Fig. 116], and at m is the bevel to be applied to the level tangent a″.
Fig. 120. Simple Method of Drawing Curves on Face-Mould.