K40 6inch adapter

thingiverse

This is a bolt on adapter for K40 Chinese lasers that come with the 4 inch computer fan as the smoke extraction system. This was designed to adapt that opening up to 6 inches which will work for many aftermarket extraction fans. I specifically use the Infinity brand of 6 inch fans. The only thing you will need is a bolt that is a little bit longer. I found mine at a local hardware store and you can bring the factory bolt to aid with correct thread pitch.