How To Draw an Ellipse Ask This Old House

boy what do we got going on here pops all right lot of people ask me how do draw an ellipse do they well not really what are you hanging out with but you know lots of times we'll make quick jig like this for something that's small or we can even make it to run router on depending on what you want you can make it any size you want this is just piece that's 90 degrees with skirt in it for the nails to ride in it and that's kind of the idea right you know ellipse has got two focal points basically exactly right so all do is take the nails with my pencil is sticking through and keep the nails in both tracks and i'll draw half of the ellipse right here bring it around keep going over to the other side look at that and have an ellipse if this board was wide enough could go all the way around look at that it does just make sense so mean an oval is an ellipse ellipse is an oval and you guys are going to use them for arched windows all kinds of doorways anything yep don't like jigs because you always make them and you won't lend them to me all right but let's say you don't know how to or don't even want to make jig and you've got to make an ellipse real quick you can do it with piece of string now we're talking all right piece of string couple of nails draw center line wherever you want it to go let's say just let's try that put the nails in the line of the board this way in this case just use center board but you know if you're doing doorway or something you have to figure it out little bit different okay so now have two points that can put my string on have nail going in that string here can take this here now before tighten it around there i'm going to stretch it out to where think the top of the arch will be so i'm going to get that pencil that we're working with now wait minute have pencil in my pocket that's special let me show you what did all right so i'm going to wrap that around like that lock it in so it doesn't move now have pencil that what i've done with it i've put notch in the pencil okay all the way around to grab the string you're right so now the string will stay in the same position on the pencil bring it over like this keep my pencil up and down straight while move tension on the spring come around draw my arch keep my pencil up and down straight have to go on the other side of the nail bring it around keep going mirror image on that side yep right around until we meet up with that one check that out and there you have an ellipse drawn with two nails and string mean what you did was you decided what size of lips you wanted how far from the center to the south side edge right here right by stretching nice strength and once you get that everything else draws itself right but can also change this too to make it bigger string looser string will give me broader tighter string will make it narrower that is very clever mean you just roll right through there yeah mean we've done that in pinch lots of times on the job site nice tip tommy thanks for watching this whole house has got video for just about every home improvement project so be sure to check out the others and if you like what you see click on the subscribe button make sure that you get our newest videos right in your feed