Complicating this is the need to mitre the insides of the dovetailed ends, since this will permit the shape to flow better than butt ends. Interesting ... as I have never made mitred dovetails to date. This is going to be a steep but quick learning curve!
I spent some time researching mitred dovetails. There is not much around. The only book I could find with directions was Ian Kirby's "The Complete Dovetail". I like Ian's work, but the writing here were not his best. There is a short video by Chris Schwarz (Google for it), which was helpful. There was also an article on the UKWorkshop forum (by Custard), which is a Pins-first method (I tend to saw Tails-first). There were one or two other articles to be found, of less assistance to someone like yours truly, who becomes easily spatially challenged. In the end I worked it out but, reflecting on the method that evolved, it does not look like those who came before. Perhaps it is a different way of doing it? I really do not know. Let me have your thoughts here. Anyway, I plan to show it for the education of those who want to learn a method.
Beginning with a tail board that has been marked and sawn (to speed up the description). Note that there is no shoulder here (which is common on butt ended dovetails). The wood is Merbau, which is hard, hard, hard. 20mm thick, as per the panels on the table ...
The aim is to saw all the tails. Forget about the mitre for now (... this is a departure from the methods I observed).
To make the removal of waste easiest, undercut the baselines (shallow cuts to avoid losing vertical) ...
Now fretsaw away the waste. Get as close to the baseline as you dare! My cuts are about 1mm ...
This enables the minimum of waste removal. You can place the chisel immediately against the chisel wall and pare/chop down halfway ...
With the waste removed, mark the mitre cuts at the sides - but do not cut them yet (this is another departure) ...
Time now to transfer the marks to the pin board.
First, here is an alternative to the "#140 trick" (the #140 trick involves creating a shallow rebate to securely connect the tail board to the pin board when transferring marks. This was popularised by Rob Cosman and Chris Schwarz, amongst others). My alternative is three layers of blue tape, which is peeled away afterwards.
Lay three layers of blue tape over the baseline. No need to be careful ...
Now use the cutting gauge (which marked the tails) to slice away the tape, leaving an edge butting against the baseline ...
This is the fence. Here it is seen with the pin board, which has a layer of blue tape on the end ...
The "fence" makes it easy to align the boards, while the blue tape on the pin board also acts as a non-slip ..
When you trace the sockets (with a knife), the outlines look like this (great for old eyes!) ...
Drop all the vertical lines, with the exception of the line on the outside at each side ...
Remove the waste in the same way as done on the tail board (undercut the baseline, fretsaw and chisel) ...
Mark out the mitre lines ...
... and drop the verticals on the reverse side...
Now saw the mitre cuts and remove the waste ...
Do this on the tail board as well - the reason it was left until now was that it would be difficult to transfer the outside tail if the mitre was sawn.
Stay about 1mm from the mitre line. Do not saw to the line. This will be more accurately shaped with a chisel.
For chiseling, use a mitre guide. This is just a 45 degree saw cut. I made a double-ended guide - to use on opposing sides ..
Take it slowly, a smidgeon at a time.
Finally ... the moment of truth arrives ... will she .. won't she ??
Looking promising as the top is pressed together with finger pressure. Then I wack it - the wood is uncompromising. The clamp is to prevent any cracking in such circumstances.
Not too shabby.
Mitres are tight ...
Now about the rounded edge ... here is the secret weapon:
After marking out, the waste is removed with a block plane, and then sanded smooth. Just lacking the inner filet ...
Enough practice. Now for the real thing. A bit more of a challenge as the panels are 500mm wide.
Regards from Perth
Derek