126 Designing and making stairs to current building regulations
Further considerations concern minor easings that
have to be made to the nosing- ends of some of the
tapered treads and to the face- side and backside ends
of risers at the points of entry into the housings. This
‘easing’ has to be made where nosings and risers (and
scotia moulds, if used) are at acute or obtuse angles to
the string, as illustrated above. For practical reasons,
the square- sided housings cannot be undercut to
accommodate these ends.Newel post details
Figures 6.55(a)(b)(c): The lathe- turned portion of the
four newels (and two half- newels for the abutment
to the walls) were finished with projecting spigots at
each end that were eventually glued into correspond-
ing holes in the square- shaped newels below and into
the handrail and handrail- caps above. The half- newels
were made by cramping two half sections together,
with a sheet of glued lining paper sandwiched
between them. After being turned, the end- grain glue-
line was easily levered apart with a firmer chisel, to
produce the half newels.
The square newels had a finished size of 69 × 69mm
and their height was governed by a marginal amount
above the wreathed string, as can be seen in Figure
6.53(c). The segmental- rounded top edges seen in
6.53(c) and below in Figure 6.55(c), to the bottom edgesdancing steps. Normally, it is the riser- faces (by virtue
of being parallel to the nosings) that do not share a
common centre.
Once the nosings were marked (including the scotia
moulds, which were to be housed in as well), a 20mm
helical margin line was established above them with the
aid of a narrow hardboard flexi rule. Then the ends of
this line were squared across the string’s narrow edges
to produce a high and low mark on the face- side edges
of the concaved side. The flexi rule was applied again to
pick up these marks and the second helix was drawn to
complete the marking out of the string’s wreathed edge.
The excessive (but reusable) waste above the helical
edge was cut away with a reciprocating- type sabre saw –
after the housing out of the steps, but obviously before
gluing the dowelled edges of the string to the newels.
Throughout the cutting operation, careful vigilance had
to be kept on both sides of the twisting helical lines.
Then the edge was finished to the lines with a flat-
bottomed spokeshave.
Tapered- step details
Figures 6.54(a)(b)(c)(d)(e): As previously mentioned,
oversized tapered treads are laid on the rod and care-
fully squared up to the rod’s nosing lines. Then the
extremities of each different shape (i.e. square winder,
skew winder, kite winder) are squared up and marked
out on the face sides. Extended parallel lines are then
marked, equal to the depth of the housings (normally
12mm), to determine the final cut- lines. However, if
a tapered- stair arrangement – unlike the one shown
here – is to be fitted in a corner, further allowances
of at least 10mm should be added beyond the cut- off
lines to compensate for any non- squareness of walls
that the site- fitter may encounter. As illustrated below,
I only had to allow extra beyond the housing depth for
the projecting tread- tenons that were to be mortised
through the two plywood strings.
Skew winder
for step # 5Figure 6.54 (a) The 90° chisel- pared, eased- nosing of
acute- angled tapered tread # 5.
Figure 6.54 (b) The non- eased nosing of obtuse- angled
tapered tread # 4 in relation to its square- ended, nosing-
shaped housing; (c) the string- housing and end- treatment
of the riser for step # 4 (similar to that required for step #
3); (d) the housing- and riser- treatment for the acute riser
entry for step # 5 (similar to that required for step # 6;
and (e) a square riser- entry, not used here, but shown for
comparison. Note that these connections to the stair- string
housings are usually wedged, as shown, but – as men-
tioned previously – because this stair was exposed on the
underside, the step- housings were not given allowances
for wedges.(c)(e)(b)(d)