# So, I want to make an 1/2 oval shape base for a 1/2 oval shape top.

 Forum topic by mahdee posted 07-15-2015 12:09 AM 677 views 0 times favorited 16 replies
 mahdee3454 posts in 1184 days 07-15-2015 12:09 AM Topic tags/keywords: question Hi,In doing so, how do I determine the angle of vertical boards that make the base?I am assuming to do that, I can’t just use a string and two nails to draw the oval. As far as the angle cuts, I am clueless at this point. Any ideas?Thanks -- earthartandfoods.com

## 16 replies so far

 distrbd2219 posts in 1863 days #1 posted 07-15-2015 01:25 AM Maybe this video will help?:https://www.youtube.com/watch?v=J48e1mVQ_Sg -- Ken from Ontario, Canada mahdee3454 posts in 1184 days #2 posted 07-15-2015 01:35 AM Thanks Ken. That will be a good reference for cutting the top. I thought I should make the base first. It is going to be made with vertical 2×4 or 2×6’s. In doing so, I have to figure out the angle cuts that follow the half eclipse. Very much like a whisky barrel sitting on its end. So, there may be a 15 degrees cut on both sides to create the curve for example. I wasn’t sure if there was a math formula that could figure the angle based on the X or Y axis. -- earthartandfoods.com DIYaholic19135 posts in 2091 days #3 posted 07-15-2015 02:05 AM Since the ellipse is not a circle…I think all the angles would be different. Yeah…. the calculus, that I can’t remember comes into play, I’m sure.I would think a line, perpendicular….to the slope of the varying curve….would give you each angle.That’s the best I can come up with…. Now my head hurts!!! -- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing? mahdee3454 posts in 1184 days #4 posted 07-15-2015 10:39 AM Thanks Randy. I think that might be the best bet. Cut the curve on a piece of cardboard, measure 4” increments and connect them to the center, place the boards on top and mark the lines inside and out. -- earthartandfoods.com TopamaxSurvivor17569 posts in 3092 days #5 posted 07-19-2015 06:51 AM It should be easy to do with the trig function tangent if you know how big both the top and bottom will be and the height. -- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence mahdee3454 posts in 1184 days #6 posted 07-19-2015 02:51 PM Thanks Bob,Assuming the top and bottom are 3’ wide and height is 32” How would the formula gets plugged-in? -- earthartandfoods.com distrbd2219 posts in 1863 days #7 posted 07-19-2015 03:27 PM Cut the curve on a piece of cardboard, measure 4” increments and connect them to the center, place the boards on top and mark the lines inside and out. - mrjinx007This the simplest way imho.I would try it first, the more complicated ways gives me a headache. -- Ken from Ontario, Canada mahdee3454 posts in 1184 days #8 posted 07-19-2015 04:01 PM I know Ken.. I think that is the way to go as well. Nevertheless, I like to see the formula as well. So many things can go wrong when I comes to wood and precise measurements. -- earthartandfoods.com TopamaxSurvivor17569 posts in 3092 days #9 posted 07-19-2015 06:24 PM Thanks Bob,Assuming the top and bottom are 3 wide and height is 32” How would the formula gets plugged-in? - mrjinx007 Maybe I don’t understand what you are trying to do? I envisioned a half an old fashioned coal bucket shape with the base and top being 2 different lengths and widths. -- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence mahdee3454 posts in 1184 days #10 posted 07-19-2015 08:01 PM No sir, both top and bottom would be same size and shape and the “wall” would be flush with the edges of top and bottom. -- earthartandfoods.com TopamaxSurvivor17569 posts in 3092 days #11 posted 07-19-2015 11:56 PM so you want the intersecting angles of the boards that will make up the vertical sides. Sorry about the false hope. I probably could have figured those varying angles on the edge of the ellipse 45 years ago when I was a math wiz ;-) but that is beyond me now;-( -- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence ChuckV2872 posts in 2943 days #12 posted 07-20-2015 12:33 AM Determining the angles for just a quarter of the ellipse is enough. So, I would probably draw it out and use a bevel gauge to get the angles. -- “And the products of wealth push you along on the bow wave of their spiritless undying selves.” ― I. Anderson jerryminer496 posts in 858 days #13 posted 07-20-2015 12:40 AM Formula? Ellipses can vary so much and the size of the “sides” can vary, too, so a formula would be quite complex, with variables for length/width/number of facets/side width/thickness … But if you draw it out full-size, you can take off the angles. Here is one example with approximate 4” sides: TopamaxSurvivor17569 posts in 3092 days #14 posted 07-20-2015 12:43 AM Depending on how critical the fit needs to be the individual pieces will need to be custom coopered, then each angle custom fit. This could get quite tedious. -- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence mahdee3454 posts in 1184 days #15 posted 07-20-2015 01:54 AM jerryminer, yes. It is too complex for a woodworking project and I should have known that before conceiving such a project. Bob, I totally agree. I think the beast course of action is to make the base and worry about the surface last. I went ahead and deviated from my original thought and am going to use a natural edge table to incorporate what I had in mind originally. Next project, if this one is successful will be a stump. It is going to take me at least 4 months to figure this one out. I have already spent the last two weeks so far to get the natural edge at a 45 degrees using a sassafras board 3” thick. Thank you for all the input. -- earthartandfoods.com

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