Replies

1. 
   BArnold | Sep 17, 2004 10:12pm | #1

   max,

   Use the 'Advanced Search' function at the upper left of the forum page.  Use the words 'ellipse' and 'oval' for the search criteria.

   Regards,

   Bill Arnold - Custom Woodcrafting

   Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

   ---

2. 
   joinerswork | Sep 19, 2004 02:28am | #2

   Max,

   Start with one corner of your rectangle (1/2 the length, 1/2 the width).  Divide each side of the corner into the SAME #of parts.  Put a dot with your pencil at each division.  Then, with a straightedge, connect the first dot on the end (near the center line) to the first dot on the side (near the corner).  Continue connecting the dots, til you connect the last dot on the end (nearest the corner) to the last one on the side (nearest the center line).  The intersection of these lines will describe 1/4 of the ellipse you want.  You can repeat on the other three quadrants, or trace a pattern, and flip and turn it to get the oval.  The more divisions, the more accurate the curve of the ellipse.

   Cheers,

   Ray

3. 
   rod | Sep 19, 2004 03:19am | #3

   Here is a mathematical way. Draw a horizontal line dividing the rectangle in half.  Draw a vertical line dividing the rectangle in half.  Let   a   be half the horizontal dimension of the rectangle and   b   half the vertical dimenson of the rectangle.  I am assuming that  a  is the larger length.  Find  c  which satisfies  c*c = a*a - b*b, in words  c  squared is equal to  a  squared  minus  b  squared.  Many calculators will do this.  Now mark two points at a distance  c  from the intersection of the horizontal and vertical lines on the horizontal line.  Fix two thumb tacks into a string which are  2a  distance apart (the long dimension of the rectangle).  Put the two thumb tacks into the points a distance  c  from the intersection point of the lines.  Now take a pencil and scribe the arc of the ellipse by keeping the string taut.   You probably have to switch the string to go from the top half to the bottom half.  As an example if you want an ellipse in a rectangle that is 24 inches by 18 inches then  a = 12 ,  b = 9 and c*c  = 12 *12 - 9*9 = 63  which  makes  c   just a little under  8 inches.  So the distance between the thumb tacks should be 24 inches and the thumb tacks are pressed in  8 inches from the intersection of the vertical line dividing the rectangle in two along the horizontal line dividing the rectangle in two.   I hope this helps, but it seems long winded for a relatively simple method.

4. 
   jagwah | Sep 19, 2004 07:25am | #4

   Here's an excell file that works