Laying Out Ellipses

Other Versions
Spanish Spreadsheets, formulas, jigs, or approximation - quick links to all methods. April 11, 2005

Question
Does anyone know how you make an elliptical layout compass with 2 sliding blocks of wood?

Forum Responses
(Architectural Woodworking Forum)
From contributor A:
If you have a spreadsheet program that can open up an Excel file, then go to this link, and download the free file. One of the worksheets has ellipse calculations and drawings that will be of help to you. Related web page: Spreadsheet Calculation Program

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From contributor B:
A simple way to do it is to just nail down a sheet of plywood in the lower quadrants with the corner at the origin and use the edge to guide the pins in your trammel. Just flip the piece to do each quadrant. There is a way to approximate an ellipse, using a three or five point method, which is simply two or three radii. It is much simpler than the above method. It is hard to tell the difference.

Here is a useful link describing all methods. Related web page: Ellipse