# Simple formula needed?

• Aug 3rd 2009, 10:18 AM
Kilroy
Simple formula needed?
Possibly a simple question. Math is not my strong point (Wink) Anyway I have an octagon and I know the the distance of each side (5.348") and I need to find out the distance of the furthest point to point. (Imagine each point of the octagon is a small hole) I just need something simple to use on a calculator. For instance to find out the spacing of square (4 hole) bolt circles (B.C.) I divide the B.C. by 1.414 and I get my spacing. Is their a simple formula for an octagonal B.C.? I hope this isn't too confusing. Thanks much
• Aug 3rd 2009, 10:43 AM
CaptainBlack
Quote:

Originally Posted by Kilroy
Possibly a simple question. Math is not my strong point (Wink) Anyway I have an octagon and I know the the distance of each side (5.348") and I need to find out the distance of the furthest point to point. (Imagine each point of the octagon is a small hole) I just need something simple to use on a calculator. For instance to find out the spacing of square (4 hole) bolt circles (B.C.) I divide the B.C. by 1.414 and I get my spacing. Is their a simple formula for an octagonal B.C.? I hope this isn't too confusing. Thanks much

What do you mean by the "distance of each side"? Is this the length of each side, or the perpendiclar distance between opposite sides, or ...?

CB
• Aug 3rd 2009, 11:20 AM
Kilroy
Quote:

Originally Posted by CaptainBlack
What do you mean by the "distance of each side"? Is this the length of each side, or the perpendiclar distance between opposite sides, or ...?

CB

Yes, length of each side sorry. Imagine numbering each point of the octagon clockwise staring in the upper left as 1. I know what 1 - 2 is and I need to know what 1 - 5 is.
• Aug 3rd 2009, 11:48 AM
Quick
If you want to know just the distance across the whole octagon (the diameter kind of segment) then you take the length of the side and multiply it by 2.61313

At least, that's what I came up with, if it seems wrong let me know.
• Aug 3rd 2009, 12:09 PM
Kilroy
Quick, I think you nailed it, my guy in the field said it was possibly 14" but that all he could get was the spacing mic'd out. Just so you know it's a valve mounting pad that is obstucted and underwater. It's very difficult to get to. Thanks again, Quick