Manual of Purpose-Made Woodworking Joinery

Designing, setting out and making stairs 123

as gluelam (glued and laminated) construction. Four

straight- grained strips of redwood were produced

measuring 23 × 3mm, which were glued and cramped

together around the step’s outer edge, between a female

jig- former and the shaped edge of the step (acting as a

male jig- former). Note that the 1mm oversized width

of laminae was to allow for cleaning- up any slight

irregularities after gluing.

Before gluing the four laminae to the male-

former – not the female- former! – they were well

soaked with boiling water to increase their moisture

content and pliability, then (after an hour or so) they

were slowly cramped between the formers without

being glued and left in this state overnight. After

being released the next day and left to air for an hour

or so, wood glue was applied and they were cramped

up again and left until the following day. After trim-

ming off the slightly oversize lengths, the top- and

underside- edges were cleaned up (to a 22mm finish)

and the segmental- shaped nosing was applied on a

fixed, overhead router.

Note that illustrations 6.51(a) and (b) show the

traditional technique for applying scotia moulds to

shape- ended steps – by applying a stuck mould to the

edges of shaped scotia boards that are then screwed to

the underside of the tread.

Bullnose riser details

Figures 6.52(a)(b)(c)(d): The approximate length of

this riser was gained by hooking up and flexing a tape

rule around the nosing- edge of the bullnose tread.

Its actual width (height) was 190mm rise minus the

tread- thickness (18mm) and the scotia- board thick-

ness (19mm) = 190 – 37 = 153mm. To set out the

fretwork pattern – which was based on a concept of

64mm Ø holes – the hole’s diameter was deducted

from the 153mm riser- height, leaving 89mm. This was

divided by 4 to create two 22.25mm horizontal bands,

one at the top, one at the bottom, and a 22.25mm

on the straight- edged tapered steps and I felt com-
pelled to use this material again. This was because
a non- carpeted stair was planned, with a varnished
pine- appearance and I did not want to see a change of
material on the treads, with a different pattern of grain
‘grinning’ through the clear varnish. The problem was
that by using 18mm plywood, I created an extra task
of bending the 22 × 12mm segmental- shaped lipped-
nosing around the bullnose end.
Figures 6.51(b) and (c) indicate how this was
done by using a technique referred to in Chapter 3

Bullnose centre point

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Tread used as

Male Former

Female

Former

4 strips of nosing laminae

Figure 6.51 (c) A plan view of the bullnose tread used as
a male jig- former and a purpose- made female jig- former
made from 18mm plywood. Three temporary wedge-
shaped blocks were glued onto the tread’s back edge to
provide four tangential sash- cramp positions (**). Note
that the 18mm ply female former was subsequently used
to make the hockey- stick shaped back- supports for the
open- boxed bullnose riser.

Figure 6.51 (d) A 3D view of the made- up scotia- board;

and (e) A true Plan View.

(e)

(d)

Plywood tread with gluelam nosing

Scotia board

Framed-up

bottom

riser

Figure 6.51 (b) A section through the actual bottom
step with its thicker scotia board and gluelam nosing; the
detailed illustrations of the construction of these – and the
open- boxed, pierced and bullnose- shaped plywood riser
are given below.