Order of Work
- Make the risers and treads
- Bevel the post
- Glue up the risers and post
- Install the treads
- Attach the finial
- Sand and finish
See onlineEXTRAS for a cut list and Essential Box Joint Jig plans. Plus you’ll find some tips on biscuit joining basics.
Box joints with a mitered corner
Two sets of coopered risers support three trapezoidal treads that step up while rotating counter-clockwise 30° at a time. The treads are secured to the risers via box joints with overwide mitered outer fingers. (Take your time to center your box joints carefully and you’ll avoid some headaches.) The coopered risers are also biscuited for added strength and aid in alignment during glue-up. To echo the coopered faces, a hexagonal post serves as a central handrail leading up to a faceted finial, while half round cutouts at the base of the risers lighten things up and add a few contrasting curves. The post is edge-joined and biscuited onto the tallest narrow riser, and the finial is secured with a dowel. I used Kentucky Coffeetree (read all about this species in Woodsense), which resulted in a very strong and tough set of steps that are still fairly lightweight.
Make the risers and treads
Mill stock for the risers and treads, making one of each about 5" overlong for setup stock. Leave the treads rectangular and about 1/8" overwide. Rip a 15° bevel along the long edges of the risers before cutting everything to length and saving the 5" cutoffs. Start the joinery on the risers. Set up a 5/16" box joint sled at the table saw (see OnlineExtras for plans) and adjust the blade height to match the tread thickness. Position a stop block for the first box joint cut on the wide risers, such that the fingers are centered across the riser’s width. My stop was 1-3/32" from the blade, but use the 5" offcut from your risers to dial in this location. Saw the first slot on each riser before removing the stop block and inserting the box joint key to complete the rest of the cuts. Repeat the process to center the cuts on the narrow risers. Adjust the blade height to match the thickness of the risers and cut the mating slots across the wide ends of the treads, again using the offcut piece for setup and positioning a stop to locate the first cuts. Flip the treads end for end as shown for the cuts across the narrow end. Lay out the taper on the treads and bandsaw close to the line before edge jointing, leaving the treads tapered but still slightly overwide.
Leave a wide edge. Position a stop block to locate the first cut on each wide riser. Install the box joint key and finish the cuts, stopping short of the other edge by the same margin.
Mirror the mortises. Cut the slots across the wide edge of each tread. Then register the sixth slot on the key and set a stop block. Remove the key and flip the tread end-for-end to saw the first slot on what will become the narrow end.
Miter the box joints
Beveled cuts at the corners combine the harmonious look of a miter with the brute strength of a box joint. Start by laying out lines on the inside face and top edge of the risers, offset 5/16" from the outermost mortises. With the inside face of one riser toward you, saw along the line until your blade reaches the upper outer edge and the lower inner edge of the box joint as shown. On the side of the riser, mark a line from the outer upper corner to the lower inner corner of the joint and saw along this line until you intersect with your first cut. Repeat for each top corner of each riser. On the outside edge of each tread, mark lines from each outer upper corner of the tread to each corresponding lower inner corner of the box joint. Saw along your lines, creating the tread miters. Pare the miters as needed to fit the joints. Once the joints are fully seated, handplane the overwide sides of the treads until they are flush with the risers.
Saw the half-faced tenon. Mitering the risers requires two cuts: The first is vertical, offset one finger’s width from the last slot, creating a final finger with a half-face that will intersect the mitered corner.
Cut the miters. The miter cuts for both the risers and treads run from the outside to the inside corner. On the risers, saw until the angled cut intersects the first vertical cut you made. On the treads, cut through to the first slot.
Make the post and finial stock
Mill stock for the post plus an extra 15" long piece for setup to size. Also mill stock for the finial to the proper thickness and width, but at least 12" long for safe handling. Draw a centerline down one of the narrower faces of each piece and tilt the tablesaw blade to 30°. With the wider face of the finial stock flat on the saw’s table and the marked face toward the blade, adjust the fence until the blade cuts a bevel that just kisses the centerline. Bevel all four corners of the finial stock, always keeping the wider faces flat on the table. Repeat with the post and the extra setup piece. Mark the center of one end of the post and finial stock and drill the dowel mortises. Finally, chamfer the drilled end of the post as shown in the Finial Detail on p. 33.
Lay out the biscuit locations on the inside faces of the wide risers, the outside faces of the narrow risers, and on one face of the post spacing them approximately as shown on p. 33. Set the biscuit joiner’s fence angle to 75° and cut the mortises for size 0 biscuits in the risers. Adjust the fence to 60° and cut a sample mortise in your post setup stock. Insert a biscuit into the sample mortise and fit it to one of the risers. The face of the setup stock and the beveled edge of the riser should be about the same width. Adjust the biscuit joiner’s fence height until the resulting biscuit joint aligns these parts, then cut the mortises in the post.
Hexagonalize the post and finial. Tilt the blade angle to 30° and set the fence so that the blade just kisses the centerline of the outer face.
Narrow support. Stabilize the biscuit joiner on narrow stock by backing up the piece with other stock of the same thickness. For more about using this cordless machine, see Tool Reviews.
Tape and glue
Lay out, bandsaw, and sand the curved cutouts at the bottom of the risers. Dry fit the assemblies, bringing them home with hand pressure and stretching painters tape across the coopered joints to clamp them. When you’re satisfied with the way things fit, apply glue to the mating surfaces and biscuits joints and clamp with fresh tape. Add one tread at a time, applying glue as you go. Loosely clamp each tread in turn, then secure additional clamps to fully seat the box joints once all three treads are in place.
Faceting the finial
Tilt your table saw blade to 45° and skin both the fence and table surface of a crosscut sled with 1/4" auxiliary material to create a zero-clearance cradle for the finial stock. Draw a line 9/16" in from the doweled end of the finial stock on every face. Align one of these marks with the kerf opening and cut a chamfer. Repeat for all six faces. Sand the doweled end back until it matches the top of the post. Adjust individual facets with a handplane if needed. Change the tablesaw blade angle to 30° and adjust the height of the blade to 9/16". Shift the skins on the sled to cut new zero clearance kerfs. Draw a pencil line 3/8" offset from the chamfer on each face. Align one of the pencil marks with the kerf and cut an angled slot. Repeat for all six faces. Set the blade angle to 90° and crosscut 1/4" past your last pencil mark, freeing the finial. Glue up the finial-dowel-post assembly. Chamfer the bottom edges of the risers and posts with a file before sanding and finishing your library steps. I used Osmo Polyx-Oil for its durability and track record of holding up underfoot.
Start from the bottom. The doweled end of the finial stock will become the bottom of the finial. Saw a 45° chamfer 9⁄16" from the edge.
Sand back to fit. Sand the bottom end back until it matches the top of post, testing the fit frequently as you sand and rotating on the dowel to find the best match.
Top it off. With the saw adjusted to make a 30° cut, flip the stock end-for-end and cut slots on each face, 3⁄8" away from the chamfer, creating the top facets of the finial before crosscutting it free.
