How can I router / cut a 8' long half ellipse

[Knottys]

Hello everyone,

looking for some suggestions here, I have a 10x5' counter that I want to router a 8 foot  half ellipse.
I basically need it to start 1 foot in from the ends.  the total  curve will be  8' long and 12" high. 

i thought of making a template out of plywood and strewing it on to my counter so i can router it that way but then again how would i make the perfect template.  I have a circle cutting jig but that would be a 20' diameter circle.

Im stuck , what would you do?

Thank you
G. knottys

 

[cgraham]

On job sites we have used a piece of azek 1x2 standing on edge. We marked the two ends where we wanted the ellipse to start and then used a stick to push the center out wards. Azek seems to bend in a perfect arc that is equal on both sides. Then we marked the workpiece, cut with a jigsaw, fine tune with a sander and then rout the profile edge.

 

[Wuffles]

Someone smarter is due along soon, but in the meantime, this is what I'd do.

I'd make a template, using one of the many methods to draw an ellipse. Freehand cut it with a jigsaw and make that as smooth as possible, then router along it.

I can't imagine a more "solid" way of routering out an ellipse than by using a template.

Hope that helps.

 

[Brice Burrell]

Check out Mike Sloggatt's article on TiC, The Elegant Ellipse.  Be sure to watch the two videos at the end of the article.

 

[wrightwoodwork]

Nice and simple mark a cross of your eclipse. One line will be a-b axis and the second will be x-y axis. Towards the A axis put a mark where you want to go and then put a mark towards the Y axis again where you want to go. So now you have your reference points marked down. Now get a couple of sheets of ply, mdf and lay them on the grid line so you can still see the lines and leave a slight gap between the sheets so you can get a nail between the gap about 3-3mm. Now get a piece of wood 10*20 at one end you can but a nail in so the point just comes through or drill hole to fit a pencil in. Now take the stick and put whatever you put in for marking on point A. Now with the piece of wood lined up with the edge of you sheet put a nail between the gap. Now you want to place the pencil on point Y again take another nail and put it through the piece of wood at the top edge of the sheets in the center where the gap is. That the marking stick. Now put the pencil back on point A. Have one nail touching the long edge and the other in the gap. Proceed to draw the Eclipse by keeping the nails touch the sheet and keep going till you have one half marked. Now move the sheets to the other half of the grid lines and carry on marking. Then cut out with a jigsaw. Years ago elu used to do jig for that very task using the router. If you need a vid doing I will do