Cutting a newel post for stringer

[thomp1983]

Hi all,

I need to cut a newel post to go over a stringer like the picture below.

I can understand how to cut out the rectanglular bottom half upto the orange line but how do I cut the angle and remove the waste?

Thanks,
Chris.

 

[big-all]

when you have achieved the rectangle accurately
you then extend the slot cutting down towards the bottom but at a slightly steeper angle facing that face as in with the newel vertical and upside down cut down to the what will be the lowest longest length then reduce the angle to what the string will be at
then go to the other face and assuming its say 42 degrees gradually reduce the angle towards 42 degrees as the slot the other side will guide the far end off the blade as you guide the handle end

keep your eye on both sides to avoid blade wander or over cutting the the slot
extra material removed by chisel drilling big hole morticer or mortice chisel or what ever you have with the most care taken on face surface with overdoing or cutting away too much on the hidden angle is not a big deal