Try to find a branch of whatever kind of wood you want to use for the siyah ,with a natural bend of the angle you want.Then you can cut both siyahs out of it side by side. This way the grain will flow around the siyahs without any runouts.
To attach them you cut a long taper on the siyah and a matching 'V' notch in the core ,then glue the siyahs in the core. After it dries you then trim the siyah in the joint flush with the core on the belly side. When the horns are glued on they overlap the V splice ,and the sinew covers the V splice on the back. Most people wrap sinew around it at this stage to reinforce the whole joint.
You can see the joint Ekwos used on his wonderful bow ,on page 3 of his son's post about it.
http://www.primitivearcher.com/smf/index.php/topic,3286.30.htmlRalph
