Looney Labs Icehouse Mailing list Archive

Re: [Icehouse] Angles

  • Fromkerry_and_ryan@xxxxxxx
  • DateThu, 01 Jun 2006 15:23:09 +0000
Eeyore,
Heck yes.

Large:  theta=94.328, bevel=47.164
Medium: theta=94.283, bevel=47.141
Small:  theta=94.204, bevel=47.102

'Theta' is the angle between two faces of the pyramid, and 'bevel' is the angle to set your saw blade at relative to the saw table.  Both are in degrees.  So the bevel angle is pretty close to the usual 45 degrees, but just a little closer to perpendicular.  If your saw is like mine and a normal perpendicular cut is with the blade at the 0 degree setting, then the settings you want to use are in the 42.8xx degree range.

You could try the calculator on this page: http://www.slyman.org/right_projects_math.php
But you're only allowed a certain number of decimal places.  That lack of precision throws off the results by about a tenth of a degree.  Luckily I already had the formulae in an Excel sheet on my thumb drive.  (Hold on a second -- my geek-o-meter just started beeping.)

So what's your building material of choice?  Plain old plywood?  I think the thickness of a normal sized pyramid wall is a little under 1/16".  Scaling that up 8x means you need to use 1/2" plywood (which is slightly undersized) to do it "right".

Ryan

 -------------- Original message ----------------------
From: "Elliott C. Evans" <eeyore@xxxxxxxx>
> 
> I know we talked about this several years ago, but has anybody
> actually calculated the angles between the sides of the various
> sizes of Icehouse piece?
> 
> I mean, if I was going to cut wood triangles on a table saw,
> what angle should I bevel on two of the three edges so that I
> can make slick-looking pyramids without any edge-grain showing?
> 
> Ryan, did you work this out?
> 
> I'm pretty sure it's not just 45 degrees.
> 
> --
> Elliott C. "Eeyore" Evans
> eeyore@xxxxxxxx
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