I am not good enough with jointery to do anything but a butt joint between the existing stock and the replacement fore arm. So I had to come up with a way to add strength to the joint.
I inletted the stock and then inserted a stiffener between the fore arm and the stock.
I had to make a jig to hold a router on the milling machine so as to be able to control the cut very precisely.
Here is the mortise in the joint.
And here is the stiffener glued in place.
