obelisk

[vliet]

I'm planning on building a display case with an obelisk top, the case is 20" square, with the obelisk taking off from the top at 45 degrees. I'm looking for a formula to determine what the compound miter cuts will be. Thnx in advance!

[vliet]

After some looking around the net, it appears that it's a 35.3 degree angle.... (still would like to know the formula though, if the bottom angle is anything other than 45 degrees...)

[dmaclusk]

Have you got a pic someplace? I'm having a hard time getting this in my head. 20" square base with the the edges of the obelisk coming up at 45 deg? I keep getting a pyramid shape in my head.

[vliet]

You've got the right vision of it, think of the Washington monument; built out of wood.... the front having a glass hinged door, with a can or eyeball light shining down from inside the obelisk.. (The monument's obelisk 'takes off' with a much steeper angle than 45 degrees)

[TDHofstetter]

Not knowing any better, and being too lazy to get my geometry reference & engineering books down offa' the shelf & dig through 'em for half an hour, I'd rapid-guess that the compounded bevel angle would be half that of the base angle - predicated upon the supposition that any two adjacent sides rise at the same angle.

Best way to know for sure, I think, might be to make practice cuts on a couple of scraps & mock up the cut, adjusting till it's right. Then measure & lemme know if my WAG was anything close to right... :)

-- Tim --




I'm too young to feel this way,
But I'm too old to think this way.

[vliet]

Here's a rough sketch (very rough....)