I am building a roof that is a octagon what is the angle where the coners meet i know it is a compound miter?

Question

evere where i have looked says it is 22and 1/2 i have tryed that are all of them soposed to be the same lengh is one angle diffrent i tried 22and 1/2 on both cuts but when i do i can only use 6 pices instead of 8 and it still off some

Answer 1

You have 16 cuts on an octagon.

360 degrees divided by 16 cuts = 22-1/2 degrees.

Check your mitre saw.

Should have a pre-set for 22-1/2 on the mitre saw.

Answer 2

its 22.5, so i dont know what your doing wrong.

Answer 3

I assume you are talking about the rafter cuts.

You don't say what the roof pitch is, so the question is impossible to answer.  

If the roof pitch is 6/12 for example, then the miter should be set at 26.75, [that's the plumb cut, and the heel cut is 90 degrees from that angle], and the bevel set at 22.5.

Changing your miter even slightly will open up your bevel so it won't fit together.

Answer 4

22.5 is correct. You must be measuring wrong. To do a square, you'd need 45 degrees, right? So that in half to double the amount of sides is definitely 22.5. Make sure all your wood is the same length on the same side. That's the best I can offer, but 22.5 is definitely what you're looking for.