Stairs with Winders

This is a basic housed-stringer staircase with a quarter-turn of winding stairs at the bottom.

Here's how it was built:

Measurements on the architect's drawings were verified on site.  The stairwell has been drywalled, the finished floors have not yet been laid.  Floors are checked for level, walls for plumb and square.

Before cutting any stock, the staircase was laid out full size on a sheet of white-painted Masonite.  Elevation, plan and side views were overlaid on a grid of the rises and unit runs.  Winder layout was tweaked until the unit runs were consistent with the flier treads and workable joinery at the newel was resolved.

A full-scale layout drawing like this is called a joiner's rod.  All of the pieces are marked directly from it rather than measuring.

The stringer stock was jointed straight before ripping to width.

A router template was made for the tread and riser housings and tweaked until the nosings fit tightly.

Once the template fit is finalized, treads and risers can be cut to final size, tongued and grooved.

Extra width was glued onto the wall stringer to take the winders.

The shape of the wall stringer was marked onto the stock directly from the joiners rod

Once cut to shape, the wall stringer was laid in position on top of the joiner's rod and all of the layout lines for the risers and treads were transferred from the joiner's rod to the stringer.

The return stringer and the newel were laid out in a similar way.

Position the stock so that defects and knots end up hidden below the treads.

Winder treads were also marked out directly from the rod.  A straightedge clamped along the nosing layout line on the rod allows for accurate positioning.

Winder nosings are trimmed square where they drop into a housing. Fit was checked with a scrap with a housing cut in it.

Housings were all cut to 1/2" deep.  the housings are tapered to allow for driving wedges to secure the treads & risers in place.

Housings are challenging where they wrap around the newel. 

Joints and angles were laid out and cut onto scraps of winder tread stock to use for checking fits of winder housings.

Wedges were made with this jig.  1:16 slope. Long wedges were made for the winders.

Assembly began with dropping all the flier treads in place.

Then the risers

Fix the risers in place with glued wedges

Saw these off flush and then wedge the treads in place.

Screw the risers into the backs of the treads while the glue sets. 

With the upper stairs now rigid, the winders are easier to assemble to the bottom.

Cant strips to secure the treads to risers are sawn diagonally out of 1 3/4" square stock

And glued and nailed into place.

Now complete, the staircase was loaded onto a trailer and delivered to the job site.

Installation constraints required bringing the staircase into the well upside down and backwards and then flipping it over end-for-end into position.

A wheeled dolly greatly simplified this maneuver.  a rectangle of plywood fastened to the return stringer provides strength and square edges to roll the staircase over on.

Halfway there...

and over...

Plywood removed, dolly extracted, and dropped into place

Fastened to the wall and ready for the finishers.