Math Experts

[Stan R]

I am building a fire pit out of a propane tank end.

The end is 30 inches across and just under 96 inch round.

I want to put an Octagon shaped shelf around the top that is 12 inches wide.

I will use 1 inch square tube.

I know or think the cut angle on all the pieces is 22.5 degrees.

How long do the pieces on the inside need to be to touch to circle on all 8 pieces.


How long do the outside pieces need to be tofor the shelf to be 12 inches wide.


Kinds like the ones in post #33 of this thread. He did a great job

Looks like he used 4 side that were a bit longer that the other 4 sides.

http://discussions.texasbowhunter.com/forums/showthread.php?t=517291&highlight=fire

Thank

[curtintex]

Using all of my math skills, my best guess is........purple.

[BTLowry]

It would take me some thinking and a piece of paper and pencil to work it out

[Stan R]

I could never figure it on paper...

[3rdShot]

Go buy a truckload of 10' sticks, and keep cutting until you get the right length. :-)

[JayKen86]

Using all of my math skills, my best guess is........purple.

Must be right. I came up with the same answer.

[Stan R]

I came up with blue...

But did find this using google who would have thought

http://www.pagetutor.com/octagon_layout/

[MikeJ]

17-5/16" for the long and 12-7/16" on the short side the short pieces.

Or something like that.

[BTLowry]

Tack up a 36" square and go from there

[Stan R]

That was hard I need a beer now...

[Wayno]

I drew it up in AutoCAD. That's the easiest way for me to get the measurements. The radius is 15" (diameter = 30"). The circumference is 94 1/4". The inside measurement of each leg of the inside octagon is 12.43". The inside measurement of each leg of the outside octagon is 21.54". Obviously, I think you are safe rounding to 12 1/2" and 21 1/2". Mitering each at 22.5 degrees is correct.

[Stan R]

I drew it up in AutoCAD. That's the easiest way for me to get the measurements. The radius is 15" (diameter = 30"). The circumference is 94 1/4". The inside measurement of each leg of the inside octagon is 12.43". The inside measurement of each leg of the outside octagon is 21.54". Obviously, I think you are safe rounding to 12 1/2" and 21 1/2". Mitering each at 22.5 degrees is correct.

Thank you very much..

[DaveS903]

This help?

[ShockValue]

I'm gonna go Not Purple.

[DaveS903]

Outside pieces