Installing Over-the-Post Handrailing, continued

Fitting the Handrail

Once the posts are installed, the real fun begins. Over-the-post handrailing requires the use of special railing sections, or fittings, to flow gracefully through its turns and rises. There are three basic types of fittings to work with: starting fittings, goosenecks, and transition fittings.

Fitting tangents. Starting fittings connect to the main railing with an upturn, or easing. For a smooth transition to the straight rail segment, the starting fitting must be trimmed square to the rake angle of the stair. Although you can buy a handrail miter jig for this, I establish the correct angle with my pitch block.

I begin by laying the starting volute or turnout flat, with its curved section sweeping upward (Figure 4). I then slide the pitch block under the curve, tread edge down and parallel to the section. At the exact point where the hypotenuse of the pitch block contacts the curve -- the tangent point -- I make a small pencil mark on the side of the fitting.

Figure 4.The correct cut location on a curved easing is established by positioning the pitch block beneath the curve and marking the tangent point (top). Rotating the block 90 degrees from its original position defines the cut line across the face of the easing (bottom).

Standing the pitch block on its riser end alongside the fitting lets me align the hypotenuse with the pencil mark. At that point, I trace the hypotenuse across the face of the fitting.

To make the resulting cut accurately, I first make a jig from the diagonal cutoff from the pitch block, screwed to a matching piece to double its thickness and mounted on a 1x2 base (Figure 5).

Figure 5.A simple tangent jig, clamped to the fence of a miter saw, makes for accurate cuts in curved easings. The 1x2 base of the jig is allowed to run long at first, and the tangent point from the easing is marked on the base of the jig, which is cut off square at that point (top). The tangent point marked on the fitting is then aligned with the end of the 1x2 as the saw blade is dropped slowly through the stock (bottom).

Goosenecks. At landings, or at the end of a flight, over-the-post handrailing commonly transitions over the newel post with a gooseneck fitting. The fitting has a cap, drilled to fit over the newel's pin top, that's mitered to a trimmable vertical section equal to two risers. A separate, curved easing piece -- which is cut to the rake angle in the same manner as the starting easing -- connects the vertical section of the gooseneck with the run railing below.

Making connections. Most rail easings come with one end already squared to a horizontal or vertical railing transition and predrilled for the rail bolt used to connect adjoining segments. The site-cut end of the fitting must also be drilled for a rail bolt. An inexpensive rail-bolt wrench, available from the stair manufacturer, simplifies this job considerably (Figure 6).

Figure 6.A built-in gauge on the proprietary rail-bolt wrench provides necessary drilling centers for bolt and access holes. Drilling the access hole before the bolt hole prevents the access-hole bit from wandering when the lead spur intersects the bolt hole.

Figuring the railing run. Before you can connect the gooseneck easing, the run railing must be cut to length. I've found that the best gauge for determining the segment length is the staircase itself. With the volute or turnout dry-connected to the lower end, I lay the railing section directly on the steps, over the layout line. I make a temporary support for the volute to hold its bottom flush with the first tread (Figure 7). The final step is to position the trimmed easing alongside the railing at the correct offset from the landing newel, then mark and cut the railing square.

Figure 7.The staircase itself provides the best way to measure railing runs. With the starting newel removed and the volute fitting connected and supported on a temporary rest (top left), the author marks the run railing for length, measuring back from the landing newel to the easing fitting (top right). The offset distance for the easing is already determined by the cap fitting (bottom).

Vertical transitions are easiest to mark for cutting when dry-mounted and leveled on the landing newel. With the railing resting in position on the steps, measure up from the top of the easing a distance equal to the height of the starting newel and mark the vertical section for cutting.

Don't drill for the rail bolt until you've checked the entire segment assembly for fit. The starting and transition newels must be both parallel and plumb. If the newels lean toward each other, you've cut the run railing or the vertical fitting too short; as always, it's better to measure strong and have to trim a little off.

I assemble fittings with a generous application of adhesive. In the center of the bonding area, I use PL400. Around the edges, however, I use common yellow wood glue, because the squeeze-out cleans up more completely -- essential for an unblemished clear finish. And I don't touch any squeeze-out until the glue has dried; this saves a lot of unnecessary sanding.

Setting Balusters

I have one unvarying standard for spacing balusters: Viewed from the side, the face of the first baluster (at the front of the tread) aligns with the face of the riser (Figure 8). The first baluster location determines the positions of the others. Whether I install two or three balusters per tread, I maintain a uniform spacing between them.

Figure 8.The face of the first baluster aligns with the riser face. Other balusters are spaced by equal division of the tread from the face of one riser to the next.

Wood balusters come in two types, pin-top and square-end, and in several lengths. The top of a square-end baluster is first cut to the rake angle, which fits into a matching plow in the underside of a proprietary handrail. The plow between balusters is capped with a fillet strip that's included with the handrail.

Pin-top balusters self-dowel into 5/8-inch site-drilled holes in the underside of an unplowed rail. After marking and drilling the baluster locations on the stair treads, I temporarily insert and plumb it and mark its location square across the underside of the rail, which is dry-fitted to the posts (Figure 9).

Figure 9.With the assembled railing dry-fitted to the newels, balusters are inserted and plumbed to establish the positions of the holes in the underside of the rail.

Once I've marked the positions of the balusters, I remove the handrail from the newel posts and lay it upside down on the stairs. Positioning the railing like this lets me drill the baluster holes plumb (Figure 10). To ensure accuracy, I use a drill with a bubble vial built into the handle, but you can also do this by eyeballing the angle of the drill bit against a try square standing on the tread. I wobble the bit slightly while drilling to ream the edges of the holes. This simplifies fitting the balusters into the holes.

Figure 10.Drilling accurate holes for pin-top balusters is most easily done by turning the railing upside down on the stair. In that position, plumb holes will lie at the correct angle to the railing.

After a complete dry-run test fit, I put a squirt of PL400 in every dowel hole -- treads, railing, and fittings -- drop the railing into place, and set the balusters singly, beginning at the bottom and working up. The top end of the railing is left loose, allowing me to lift it as needed to insert a stubborn baluster or add a dowel bolt. But when I drill the underside of the railing, I make the holes deep enough for some vertical play, so that I can lift and then drop the balusters into the tread holes.

Unlike yellow glue, PL400 is forgiving stuff, with a sufficient open time to work a rail run without dripping or forcing me to rush. It also fills small gaps around dowel ends, making a rugged, permanent connection.