First let me address a point of confusion that I inadvertently created. My intent all along was and is to install this bench just INSIDE my front door. Given the name of the project and writings in my first post, I can see how I created the impression that this bench was going to be outside my front door. Anyway, this bench will live inside the house.
My time in the shop today was stressful and long. The day began easy enough. I cut and fitted the second long rail. This went smoothly. Then it was time for the seat.
I marked the length from the shop drawing and surface planed one face. Checking for and removing any twist or wind. I then squared the long edges to this prepared face. Using a marking gauge I found the narrowest point of thickness. With the gauge set to that narrowest point, I marked around the entire seat board. Then I planed the remaining face down to this gauge line. I verified that the two long edges were exactly parallel. This is of paramount importance for marking out the mortises. Then came the stressful bit.
The seat requires eight angled mortises. These need to match the tenons exactly, or a least very closely. If they are off by very much the leg assemblies will refuse to install or worse, the leg assemblies will be torn apart. Since there are slight variations in the assembly the layout of these mortises needs to be pulled directly from the actual assembly. So I dry-fitted the base assembly using clamps to pull all of the joints/shoulders tight. Then I marked the outermost position of the tenons directly onto the seat. Next I measured the actual width of each tenon and marked this onto the seat. Then I measured the distance front to rear at the base of the tenons. A little math gave me the inset from the long edges of the seat to the outer faces of the tenons. Now I could set a mortise gauge and mark out all of the outer mortise locations on the bottom of the seat. I then reset the gauge to account for the distance between the tenon pair and marked out all of the remaining mortise locations on the bottom of the seat. Whew!!!
To establish the locations of the mortise openings of the top of the seat is a little less involved. All that was required was to extend one set of marks to the end of the seat board. Then using the bevel gauge, set to the correct angle, I wrapped these lines to the top of the seat board. From there it was just a matter of setting the mortise gauge to match the additional inset created by the angle of the legs. I fully intended to take photos as I did all of this but ended up being too wrapped up in my work. You’ll just have to live my sketchy explanation.
I tried two methods of chopping these mortises. The first method was to simply tilt the chisel to match the angle of the mortise. This worked but I found it hard to control the chisel as well as difficult to maintain the correct amount of tilt. The second method worked much better for me. For this method I used a smaller chisel that would allow me to chop a plumb mortise at each location. Then I pared away to remaining wast to give me an angled mortise hole. This method was quick and allowed a good bit of control in the angle of the mortise walls.
After chopping all of the mortises I disassembled the base and fine tuned each leg to its corresponding mortises. This went smoothly. Only a small amount of trimming was required for each leg to seat into its new home. Now it was time for the moment of truth and dry fit the entire bench.
The one quirk of this design, which is also one of its strengths, is that all of the parts have to be assembled simultaneously. As each leg pair is driven into the angled mortise they start out wider and are drawn closer together as they are driven home. This necessitates that the short rails must be loosely installed and will only fully seat when the legs are fully seated. Since the long rails tie the leg pairs together, the whole lot must be driven together a little at a time and evenly. Each joint must be monitored to ensure that it is seating at the same rate as the others. Twenty minutes later and I finally had the assembly together. Luckily it will be a few days before I have to try to take it back apart.
The only joinery left to cut for this project is the housing dados in which the end caps will be installed into. These are mostly decorative but do add a measure of support to the ends of the long rails and serve to keep those ends parallel over the course of time.
It’s been a long time goal of mine to build a project that did not require glue or any fasteners. This may finally be my first project assembled without glue. The design, joinery and wedges will be more than enough to hold this bench together for a very long time.