Post 15 in a series on the design and construction of a dining table which takes its cues from a unique Ming period side table. Previous posts in this thread, along with other topics, can be found in the 'blog archive' sidebar to the right side of the page.
This time around I'm working on the 'ribs' which attach to the 'spine' or central rail of the table. In the past few posts I have been cutting out that central rail, and concluded the process by mortising for the battens, or 'ribs'.
The connection through the central rail will be accomplished by a variant of an open mortise and tenon called sao tsugi. Tsugi means 'connection' and sao means 'rod' or 'pole'. Typically this connection is fastened using a pair of opposed and angled wedging pins, or shachi sen. I've detailed this joint extensively, including many variant forms, in the 3rd volume of my Art of Japanese Carpentry Drawing essay series - please excuse the shameless plug- and here is a picture from that volume of a typical sao tsugi:
In this case, I want the table structure to be more readily demountable, so I have decided to forgo the shachi sen and instead use a komi sen, or peg. That's right, I'm violating one of the guidelines for the construction of this table, in which I sought to eliminate or reduce greatly the use of glue and pegs. In those cases were I am given a choice though between gluing or pegging, I will opt for the peg. In the original table, lacquer was used as an adhesive in place of any pegging for the joins between the battens and table rails, so I am choosing instead to use pegs along with some Japanese joinery techniques. I feel it is a better solution. At least all of the pegs I will use - and there will be a dozen in total - are not in view unless one lays underneath the table and looks up. So, a compromise is necessary, but a happy one.
After laying out the joints, I used the hollow chisel mortiser to process the peg mortises and rough out the rod mortises:
Then I cleaned up the rod mortises and squared up the ends of the trenches:
Now it was time to process the mechi, stub tenons, on the end of these particular battens. First i processed these slots horizontally across:
In the above picture the orientation of the batten is upside down.
Next step was to rebate the sides of the battens to form the stub tenons:
Setting those battens aside for the time being, I went to work on the rod tenons on the corresponding battens. Again, layout first, then I did the rip cuts using my resaw:
Rip cuts complete:
Crosscutting next, revealing the rod tenons in rough form:
A step later, a small rebate is processed on the tip of the rod tenons, and I have also begun work on the first set of battens again, which also have rod mortises on their opposite ends:
While both ends of the battens have rod mortises, there are some differences in the end treatments, all of which will be shown in the next post.
I also moved along today with the main frame rails, the undersides of which I relieved in much the same manner as I had for the central rail:
Additionally, I dimensioned the long rails down 0.25" relative to the short side rail height.
The short side rails receive a similar relief treatment on their lower edge:
All for today. I'll be back at the fun again tomorrow and hope to make 'solid progress'. It is real wood after all (mild stab at humor there...)