#### Iplayfarmer

##### Super Member

GuglioLS said:According to my calculations it should be a 60/30 compound angle.

60* you got, cuz that's what you want.

I came up with 30* because.....you want all three legs to be roughly equal "distance" or angles apart, so thats 360 / 3 = 120* since you are using a square (4x4?)to mount the legs to they are 90* apart, so one leg is mounted and the others are referenced to the starting point. The next leg is already 90* away so add 30* to that 90 to get to the 120*.

Larry

You are right!

I had my references mixed up. I want 30* from perpendicular to the square (60* from parallel). Furthermore I actually only want the leg to be 30* from horizontal (60* from vertical).

gizmo said:In your case I think you are talking about a 'three sided pyramid'

These formulas should solve just about any miter problem. Start by getting a value for 'A' based on the number of sides. Then figure the miter and bevel. Ensure you calculator is in degrees mode and the value for 'SLOPE' is in degrees. If you load these into a spreadsheet program you can create a chart.

A=90-(180/#SIDES)

MITER=90-(ARCTAN(SINE(SLOPE)/TAN(A)))

BEVEL=ARCSIN(COS(A)COS(SLOPE))

This works great for picture frames and situations where two pieces come together to make a corner. The scenarios I'm talking about are where a single piece needs to be mitered to mate with a flat part of something else. I think there's a way to extrapolate the info from the formulas you've posted to get what I want, but I haven't gotten my head around it yet.

Reg said:I don't see it as a problem.

Just set the mitre cut to (60 degrees or whatever) and the bevel cut to (60 degrees or whatever) and cut. Do the (90 minus your whatever) at the end where they touch the ground.

I tried to figure the dihedral angle of that dodecahedron thang a couple of months ago - gave up.

This is great in this particular situation if I were cutting wood on a table saw. I'm cutting metal with a skinny wheel. I need to know the actual angle of that second cut in relation to the log axis of the leg in the plane of the side of the leg.

I actually just got out of the garage and did what you had suggested with a piece of wood and then measured the angle I needed. It worked out to be just about 35*.

I consider that cheating. Threre's still got to be some kind of formula or method of calculating.

P.S. I'm pretty pleased with myself for figuring out how to quote multiple people in a single thread.