Replies

1. 
   mike_guertin | Jul 23, 2003 04:19am | #1

   Ellipse layout has not been covered in FHB.  I proposed the idea and am waiting for the editors to give me the go-ahead. 

   There are formulas to determine the foci to draft the ellipse for specific situations of known widths and heights.

   Do you have specific sizes you are looking to create or just looking for specific information?

   mg

1. 
   RIPVW | Jul 23, 2003 05:54am | #2

   i have the same problem with my garage door arches.   they are 8' wide and 2' high.

   (the arch will start at 6' high on my jamb/casing and peak at 8' in the center)

2. 
   Joe_Fusco | Jul 23, 2003 12:01pm | #3

   Guest,

   FHB the magazine hasn't addressed the situation, but its be discussed here a zillion times. A quick search of the archives will produce much information on the topic. You can get an overview of the ellipse in general here.

   One reason for using elliptical arches is to deal with openings of varying widths, while keeping the "tops" all at the same elevation as in the illustration below. A simple way to layout an ellipse is to first determine the width of the opening needed. Then determine how much of an arch you wish to have above the "spring line"(see the drawing).

   Draw a line the length of the openings width and from its mid point draw the line equal to the height of the arch.
   Swing and arc from the top point of that line equal to half the length of the width of the opening.
   The arc will cross the length line in two places called the foci.
   Knowing the location of the foci you can then use any number of methods to construct the ellipse.

   If this at all sounds to wordy then this will help clear things up.

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   Edited 7/23/2003 5:06:12 AM ET by Resurrected

1. 
   RIPVW | Jul 23, 2003 05:31pm | #4

   so then how do i draw the arch from the foci?  ripvw

1. 
   Joe_Fusco | Jul 23, 2003 06:53pm | #6

   ripvw,

   You can read this once again for it tells you how to go about drawing the ellipse.Or. . .

   "Once you have located these points you can construct this ellipse by the string method. Driving nail at each focus point are and one at the top of the minor axis, you then stretch a string around all three nails, one other option would be to use picture hanging wire because it has less give then string, pull it as tight as you can and “tie” it together.Now remove the nail at the top and place a marking device there and just begin to move it, it will follow a path that is defined by the string and trace out you ellipse. Now you have all you need to know on how to layout any regular ellipse, just plug-in you numbers to define yours."

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2. 
   eborg2 | Jul 23, 2003 05:41pm | #5

   Joe,

   Just passing through or are you back to lend some much-needed wisdom to this forum?  Hopefully the latter.

   Good to see your name again; I miss your discussion board.

   Best Wishes,

   Eric

1. 
   Joe_Fusco | Jul 23, 2003 06:55pm | #7

   Eric,

   The boards are still there and you're more then welcome to visit ;-).

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