June 7th, 2018, 01:02 AM  #1 
Newbie Joined: Jun 2018 From: Norway Posts: 2 Thanks: 0  Constant angle protractor?
Is there a protractor/compass that keeps a constant angle where one arm automatically moves the other arm? Say the protractor is closed at a 0 degree angle, you move one arm and the arm follows exactly opposite to it on the other side? Protractor.jpg 
June 7th, 2018, 01:35 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,472 Thanks: 2039 
I doubt it.

June 7th, 2018, 02:00 AM  #3 
Newbie Joined: Jun 2018 From: Norway Posts: 2 Thanks: 0 
Mmm, there must be something like this, if not a geometry tool 
June 7th, 2018, 03:49 AM  #4 
Global Moderator Joined: Dec 2006 Posts: 20,472 Thanks: 2039 
Various adjustable linkages exist, so perhaps there's one that would do what you want if set up correctly.

June 7th, 2018, 06:42 AM  #5 
Senior Member Joined: Apr 2014 From: UK Posts: 903 Thanks: 331 
You want one of these: https://image.dhgate.com/0x0/f2/albu...PYXpbhA857.jpg 
June 7th, 2018, 06:49 AM  #6 
Senior Member Joined: Apr 2014 From: UK Posts: 903 Thanks: 331 
If you attach a piece of cork to the end and point a laser distance measuring device at it, you can read off the angle 
June 7th, 2018, 06:58 AM  #7  
Senior Member Joined: Jun 2015 From: England Posts: 905 Thanks: 271  Quote:
The simplest ones are just two arms like you show with a large locking wingnut at the pivot so you can set the angle. Equally my adjustable draughtsman's square has this ability.  
June 7th, 2018, 09:46 AM  #8 
Global Moderator Joined: Dec 2006 Posts: 20,472 Thanks: 2039 
What causes the arms to move in opposite directions?

June 7th, 2018, 11:31 AM  #9 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,931 Thanks: 1126 Math Focus: Elementary mathematics and beyond 
Build one and patent it, then see how well it does.


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angle, constant, protractor 
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