This is a basic model of an Octagon Junction Box that I designed using measurements based off a real octagon box. 

I needed to fit an octagon box in a project I was designing, so I quickly designed the octagon box in order to get the right tolerances, so the real box could fit. 

Thought I'd post the reference model here in case someone else needs it in the future. 

• Not 100% Accurate but it serves its purpose (+/-  2mm tolerance)

(I don't recommend printing this as I didn't design it to be print it, and it's only 1mm thick, so it'll be very weak if you decide to print and use it).