Joining 2 Arcs

King1ove,

As I (still mis)understand it, you wish to have the join of the two segments (after joining the paths) appear like a common Butt Cap (horizontal at the bottom) rather than as a spike. The spike or sharp corner is there to create a single outer corner with its sides parallel to each of the segment ends and work that way unless the sharpness of the angle is too large for the Miter Limit, in which case it changes into the double corner like the Butt Cap, so to force a sharp corner at sharp angles you can increase the Miter Limit.

And in your case you can force the double Butt Cap like corner by decreasing the Miter Limit, hence my suggesting your setting the Miter Limit to 1 in the Stroke palette.

Did you try it?