Re: Construction details
Dave Mount
>Several have asked about the construction details, I guess I can't avoid sharing them and exposing my dirty little secret. It�s an easy project; you can make one in a long evening, at least if you don�t have to spend too much time on stock prep (or if you have the appropriate apprentices).
The dimensions are 16" wide and 24" tall; intermediate steps are at 8" and 16". The sides are 14.5" wide at the base (more on that below). The back of the sides tapers in 1" over its length. I did this to move the "tipping point" back a little; I was afraid it might be a little unstable if I didn't, though aesthetically, I'd rather the back side was completely vertical.
The sides begin as three boards, two 4.5" wide and one 5.5" wide. Usually make these circa 3/4" thick, but it's not critical. The narrower side pieces are 8+ and 16+ inches long, the wider 24"+. I leave the side boards a little long until after they are glued and I can cut them all at once. The three treads are all 4.5" wide and 16" long. If I've got the stock thickness, I leave the treads thicker, like 7/8" -- I think the dovetails look more interesting when they are joining stock with different thickness.
Cut the treads to final length and square one end of each side board. Decide what pieces go where and label them all (this is really important to keep track of when you start to cut the DTs). Then lay out and cut all the dovetails. If the steps are a different thickness than the sides, make sure to get the right gauge marks on the right pieces. For the top step, lay out the dovetails so the front of the top step is flush with the inside edge of the long side board. This makes the back half pin 1" wider than it "should" be; that is dealt with when the sides are tapered later. I don't cut the taper until after the sides are glued together -- it's a lot easier to clamp if everything is still parallel.
Mark the front edge of the back and middle side boards 8" down from the top -- these are the index marks to see where to align the pieces when the sides are glued. Now my embarrassing secret. Because of arch in the bottom the sides, all the weight of the person is born by the glue joints on the sides when they are on the middle step, so you are really depending on that joint. This is especially of concern at the front, where the remaining glue joint is relatively short. To help reinforce this, I used some. . .ah. . .er. . .�oval splines� to reinforce the joints. If you wanted to be completely neanderbub about it, you could use splines set in stopped grooves. An even cooler approach might be to inlay butterfly keys to the joints after assembly. Haven�t done that, but it might look pretty interesting and would keep the joint from sliding if the glue starts to fail. Whatever you use, keep track of where the cutout will ultimately be, so you don�t end up exposing internal joinery when you cut the arc later.
After the sides are glued up, cut the bottom square, 24" down from the top of the highest step. Make the circular cutout to make the �feet�. Mark in 1" from the top of the top back of the side, and cut a 1" taper along the back. Rather than measuring in, you may want to dry assemble the top step and just mark where the top step meets the side, and taper down from there. That�s actually how I do it, though in theory there�s no difference.
Dry assemble everything. All that�s left to do is fit the stretcher. The sides are usually parallel on their own, but if the back legs are splayed in or out, cut a spacer the right length and clamp it in place to put the back legs where they are supposed to be. The size of the stretcher is unimportant, I think I usually make it about 2.5" wide. Cut the ends into a dovetail, then transfer the marks onto the sides (I think I usually put it about 6" up or so) and cut the sockets for the dovetailed stretcher. Glue it all up.
The finish is personal preference. I like shellac because it�s fast, easy, and forgiving, but it makes no difference. Be aware that film finishes can be slick underfoot, particularly in stocking feet.
My only discomfort with the design is the reliance on the glue joint as, presumably, someday it will fail, and a failing stepstool is a disquieting thought. Builder beware, the stool is only as safe as that glue joint is strong. In addition, although it looks nice, it might not be the safest stool in the world because it�s possible for your foot to slip forward between the steps since there is no riser. On the other hand, I�m not sure I�ve ever seen a stepstool with full height risers.
Hope I got all that right! If anyone builds it, let me know how it goes.
Thanks.
Dave
