As a part of a large candle-holder project I am making an 8-sided pyramid. I need to figure out the table saw blade angle for the miter-cuts. If you know how to do this, could you check my work?
I am using this calculator:
http://www.pdxtex.com/canoe/compound.htm
I started with the slope calculation. The pyramid is 9" across at the base, so the Horizontal Run is 4.5". The Vertical Rise is 18.75". The resulting slope is 76.5° (76.504 to be exact).
It has 8 sides so the included angle shows as 135°. That calculates to an end angle of 5.5° (5.522) and a bevel angle of 22° (21.84).
Does this seem reasonable, before I try it on lumber?