Thanks! Book marked the site. Now if I can just remember that I did it the next time I need to layout some segments.

Hey guys, not to dismiss the neat segment video but to augment it, check out this video.

I have the original wooden set and it's a great tool.

 

I can remember doing a lot of this compass and straightedge construction in Jr. High, and I still use a lot of it in the shop.   I have a bachelor's and master's degree in theoretical mathematics.   In one of my final master's courses, we spent several weeks studying something called Galois Theory. (https://nrich.maths.org/1422).

 

The professor wrapped up by saying, "And that's why you cannot trisect an angle with compass and straightedge."   This was one of those long-unproven or -disproven theories that over the years attracted a lot of crackpot arguments.   We sort of all looked at each other and he spent the rest of the lecture explaining why.

 

As for circles, https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwiZ27ejufTOAhXqx4MKHXO7AesQFggeMAA&url=http%3A%2F%2Fwww.cincinnatiwoodworkingclub.org%2Fportals%2F0%2Factiveforums_attach%2Fdrawing_circles_by_keith_mealy.pdf&usg=AFQjCNExjZHfRMXY9IDLpm7HCaxr0QLByQ

The club web site has been re-done and the link above is no longer active.    I'm uploading a copy here.Drawing Circles by Keith Mealy.pdf

Wow... You guys are great at spending my money...

Am I the only observer hearing a little voice saying, "well, if you want accuracy, try sharpening that pencil first!"  ?

 

As for angles, I'm still stuck on mils for anything worth shooting at.