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Drawing

Equilateral triangle

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colin calver03/09/2019 11:02:04
28 forum posts
4 photos

How would you go about establishing marking out lines on a piece of stock 3 inches square to achieve biggest equilateral triangle. Thanks

JasonB03/09/2019 11:06:22
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Draw 60 deg line up from one corner then a 60 deg line from opposite corner, two lines will meet about 10mm down from the top.

triangle.jpg

EDIT you could actually get bigger by tilting the base side

Edited By JasonB on 03/09/2019 11:16:56

David Jupp03/09/2019 11:47:47
701 forum posts
17 photos

Taking that a bit further.

triangle.jpg

 

So if stock is a square, or you have a square marked out.  Start in one corner - draw 2 lines at 15 degrees to sides of square, join the points where these 2 cross the other sides to make 3rd side of triangle..

 

Or set callipers/compasses to 3.106" ,  start from one corner of square, where compass arc crosses sides of square gives other 2 corners of triangle.

Edited By David Jupp on 03/09/2019 11:48:18

Edited By David Jupp on 03/09/2019 11:52:25

Journeyman03/09/2019 11:48:58
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627 forum posts
98 photos

You can get a bit bigger triangle by rotating it about one apex (not sure if that is the right term but one corner) , don't ask me how you would set it out except by trial and error.

David beat me to it!

John

Edited By Journeyman on 03/09/2019 11:49:43

Andrew Johnston03/09/2019 11:56:07
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4936 forum posts
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Simple geometry, for a unit square the side of the largest equilateral triangle that can be inscribed is:

2*SQRT(2-SQRT(3)) ~ 1.0353

and the angle is 15 degrees as illustrated by David.

Andrew

Nicholas Farr03/09/2019 12:54:21
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1997 forum posts
956 photos

Hi, if your piece of stock isn't exactly square on any corner or if it is longer one way and you don't do cad, you can draw a square on a piece of paper that will fit onto your stock and mark the 15 degree lines off with a protractor and then cut the triangle shape out and glue it onto you stock and follow the edges to cut it out.

triangle drawing001.jpg

Regards Nick.

Edited By Nicholas Farr on 03/09/2019 13:01:58

colin calver03/09/2019 13:59:29
28 forum posts
4 photos

Thanks guys. Hours of beffudlement sorted in minutes.

larry phelan 103/09/2019 19:02:20
527 forum posts
11 photos

As I have found out many times, it.s all part of the service !

Long may it last !!

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