How To Draw an Ellipse | Ask This Old House
In this video, This Old House general Contractor Tom Silva shows host Kevin O'Connor an easy method for drawing accurate, smooth ellipses.
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Tom Silva and host Kevin O'Connor meet back at the shop to discuss drawing ellipses. After showing Kevin a jig he built, Tom gives him a quick lesson on how to draw perfect ellipses with just two nails, a string, and a pencil.
Difficulty: 1/5
Time: 5 minutes
Cost: Under $20 in most cases
How To Draw an Ellipse
Drawing accurate ellipses can be tricky, as they often come out uneven or slightly lopsided. However, if you need to draw a quick ellipse to make a template or guide, this method will help.
1. Lay the workpiece out and draw a straight line in the center of the board. Also, use a utility knife or pocket knife to cut a small kerf near the base of the pencil (toward the tip).
2. Lightly drive two nails into the workpiece along the line. Spacing will determine the shape and size of the ellipse, so this may take some experimenting.
3. Tie a knot on one end of the string and place it over one of the nails. Loop the other end of the string around the other nail. Adjust the string's length, so the ellipse reaches the desired height, and then wrap the rest of the string around the nail and tie it securely in place.
4. Loop the string around the pencil's kerf and slowly pass the pencil along the workpiece, starting outside of one nail and ending outside of the other nail. Flip the string over to the other side of the nails and repeat. This should result in a perfect ellipse.
5. While the ellipse may be perfect, it might not be the perfect size or shape. Adjust the nail spacing or string length to tailor the size and shape.
Where to find it?
Measure out your center line and place a nail at each end of the line leaving a little space outside. Wrap your string around the nails but stretch it up to where you want the top of the ellipse to be before securing the string to the nail. Using a notched pencil, set the string into the pencil notch, keep the pencil straight with tension on the string, and bring the pencil up and around to create your ellipse.
You can find all the materials at local home centers.
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Materials:
* String [amzn.to/3NtzCKz]
* Pencil [amzn.to/3u92Yag]
* Thin scrap wood or luan [thd.co/38qW0FA]
* Two nails [thd.co/3OSWJj3]
Tools:
* Ruler or straight edge [amzn.to/3yptTBc]
* Hammer [amzn.to/3QSh61n]
* Utility knife or pocket knife [amzn.to/3NsHGeA]
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From the makers of This Old House, America’s first and most trusted home improvement show, Ask This Old House answers the steady stream of home improvement questions asked by viewers across the United States. Covering topics from landscaping to electrical to HVAC and plumbing to painting and more. Ask This Old House features the experts from This Old House, including general contractor Tom Silva, plumbing and heating expert Richard Trethewey, landscape contractor Jenn Nawada, master carpenter Norm Abram, and host Kevin O’Connor. ASK This Old House helps you protect and preserve your greatest investment-your home.
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How To Draw an Ellipse | Ask This Old House
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Not gonna lie. Been doing carpentry off and on since I was 15, this is one of the coolest things I've seen. Thank yall
Tommy Silva is a bad @$$ bro.
So much math happiness here! I use the string method in my classes.
string theory?
Am proud of you guy's, you're the best, I hope that other carpenter's doing your kind profession be as excellent as all of you in TOH.
Muy bien
This method is really cool,don't know how many times I've took an image off the internet and had to adjust it to fit,This method makes it so simple, thanks to tommy and Kevin🤗😎🤗😎
That is so net,never would have thought of that. Nice
How amazing 👏 Thanks, Y'all!
That’s just invaluable tricks of the trade .. great stuff
Nice tip! Thanks for sharing 🙂
This is SO cool! ❤
Clever idea on the notched pencil. Will definitely use that trick. I build tub decks all the time and I use a similar method.
Here for that same reason
Notched pencil trick is brilliant, never seen that before.
I remember doing this with nails for the loci and a piece of string.
Couple nails, a grooved #2 and a piece of string. This is were I come to get smart.
Tony is the MAN!
Good job Tommy. I didn't know you were smart. :)
Clever
Kevin’s looked off from Mr Silvia’s? Was that because of keeping the pencil straight up?
❤
but how do you match the desired length and width?
Very educatif
Thanks Pop aww, you're welcome sonny. Lo
I understand how to adjust the height of the ellipse, but how do you get the width?
“Height” and “width” on an ellipse cannot be adjusted separately. The only parameters that can be adjusted are the “major axis” (distance and orientation between the two foci (nails in this example) and the “minor axis” (length of the perpendicular bisector of the major axis). Changing the “height” will alter the “width” and vice versa.
Another way to draw a partial ellipse or curve between two points is by bending a thin flexible piece of wood between three nails (or clamps). The outside nail goes in the middle and the other two nails are on the other side of the wood piece at the ends. My $0.02.
andy been eatin
A variation on that idea is a loop instead of a knot to the nails.
Ok, I must ask. Why would you need to do this? I heard him say something about the door. But for what on the door? I assume it’s to help with installing to visualize something.
Not on the actual door, an archway over a door. But I am not clear about the practical applications of this either 😁
I use this method for building tub decks to be tiled all the time.
Address post hanging sign
years ago we built a deck with a screen porch and used the string method to make trim boards between the support posts. Looks so much better than straight or square cuts.
How he did that notch in the pencil?
I don't know. Maybe chuck the pencil in a power drill and use a file or something to make the groove.
@@flat-earther ... that can work, and you could also hold it to the edge of a bench grinder or table saw, then give it a spin.
And then Kevin used the same string and pencil to draw a bigger ellipse.....
Need more electrical content
Who you hanging out with?
String method is fine, but a pair of dividers/compass is much faster and more accurate.
How? An ellipse is not a circle and has different mathematical properties.. Dividers/compasses are for drawing circles, not ellipses.
the way my jaw dropped
How did you even find that out? You were meant for this.
I thought they were going to draw an eclipse. 🌙
LOL! That was my first thought as also.
First
So cool! I’m sure all you family and friends will be oh so very proud of you. I bet your excited to get your trophy and plaque in the mail. Be sure to take a picture with them and post it, when you get them.
@@johnlebzelter4208 😂😂😂
@@johnlebzelter4208 little do you know, I already have three of those first commenter plaques signed by Tom Silva so 🖕🏻🖕🏻🖕🏻🖕🏻
The last two points did not meet as intended, sorry.
Probably because doing the second half Tom had the string looped around the pencil.
@@flat-earther ... different people will also hold different tension on the string.