[TheForge] lamp shade

[David E. Smucker]

I have been waiting for someone to raise this question.  I can't see how you 
need anything other than a 90 degree angle for the vertical side pieces.  If 
you take a horizontal slice through a truncated pyramid it will be a square 
and those angles must total 360 and be 90 each or it isn't a square.  Now 
the included angle of the piece across the bottom will be something less 
than 90 and the angle across the top will be something more than a 90.  I 
would do the top and bottom out of flat stock with tabs welded on to hold my 
filler material.  Take a piece of paper and fold it into a 4 sided payramid, 
the angle of the fold is still a 90.  Or am I missing something?

Dave Smucker

----- Original Message ----- 
From: "Janet Rivera Switzer" <tiquose at fone.net>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Thursday, November 02, 2006 10:24 PM
Subject: Re: [TheForge] lamp shade


> I'd sure like to know how to do the math to figure out what the angle 
> really is
> when you build a truncated pyramid. How did you come up with the 110 
> degrees, Andy?
>
> Janet Rivera Switzer
> blackbearforge.com
>
>>  I don't do a lot of light fixtures, but I'm doing one for my sister that
>> has a lampshade in the shape of a truncated pyramid- four sided, tapering
>> box, you've probably seen a million of them.
>> The plan was to use light angle iron for the corner pieces, but obviously
>> when you slant all four toward a "vanishing point", the 90 degree angle
>> becomes not a 90 relative to the adjoining sides.
>>
>> Somebody on this list has dealt with this situation, I'm sure: do I heat 
>> and
>> flatten them slightly, or is it easier to make 110 degree angle with 2 
>> plain
>> flat strips, or what? Suggestions, ideas, ridicule, all welcome. :)
>>
>> Thanks,
>> Andy Gladish
>> elementfe.com
>>
>>
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