November 12, 2011
With the skylight finished, it was time to get the stairs and railing rebuilt. I did some planning in SketchUp, to work out the details:
The basic structure of the stairs is reused and new treads and railing components are fabricated and installed. The treads will be 1/2" plywood (like the floor above) and have solid wood nosing, with the nosing dadoed to receive the rabbeted edge of the tread:
The posts are built up, using many parts. A piece of solid wood makes up the core that is 2-1/2" x 2-1/2" x 39" high. This is then wrapped on all four sides with 1/2" plywood to increase the size to 3-1/2" square. The trim parts are solid wood:
There are "L" shaped pieces that cap the corners and blocks of the same thickness that go between them, to create the 'frame and panel' look. The moldings that wrap the top and bottom are solid wood and were cut using the router table and table saw.
The top section exploded view:
The bottom section exploded view:
The bottom section is wrapped with two additional layers of plywood, to thicken it and the outermost layer has mitred corners. Its final dimension is 5-1/2" square at the base.
The post in place, before it was painted:
At this point, the treads are all made, fitted and put in place. These are fastened with construction adhesive.
My plan called for twenty balusters, and I cut these with a simple taper. I used a taper jig on the table saw and sanded each baluster smooth with the belt sander. The square tenons on the end of each baluster were cut on the table saw:
To bolt the lower post securely in place, I left the outside panel off the bottom section. The post is glued with PL Premium construction adhesive, dowelled to the floor with 3/8" threaded rod and bolted to the bottom riser. After the bolts are tightened, the panel is put back on.
The upper post is doweled to the floor with four pieces of 3/8" threaded rod:
These protrude about 1-1/4" and are glued into the post. This post gets lateral support from two other directions and these dowels will be quite adequate to secure it.
The upper post in place. Getting the posts painted before installing is a good idea. I used oil based flat and sprayed on several thin coats:
I made a plywood layout jig to accurately mark the mortises for the balusters.
A 3/4" drill and wood chisel are used to cut the mortises: