By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th


Equilateral triangle

All Topics | Latest Posts

Search for:  in Thread Title in  
colin calver03/09/2019 11:02:04
29 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
18098 forum posts
1993 photos
1 articles

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.


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
728 forum posts
17 photos

Taking that a bit further.



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
801 forum posts
141 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!


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

Andrew Johnston03/09/2019 11:56:07
5497 forum posts
647 photos

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.


Nicholas Farr03/09/2019 12:54:21
2262 forum posts
1099 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
29 forum posts
4 photos

Thanks guys. Hours of beffudlement sorted in minutes.

larry phelan 103/09/2019 19:02:20
718 forum posts
14 photos

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

Long may it last !!

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Allendale Electronics
Eccentric July 5 2018
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest