Do you need a small, effective workshop dust extractor with parts you probably already have lying around?
This one works great at sucking up and separating fine particles from cutting & sanding materials like wood and foam . It can separate chalk dust from the air. A device like this one will save both to save your lungs and vacuum cleaner bags.
After reading a few other dust extractor related Instructables posts, i got the basic idea of how to make a cyclonic dust extractor
But instead of messing around fabricating all the parts out of flat sheet stock i tried making one out of recycled PET soda bottles that had the same basic cone shape already. They also had another advantage, which was the built-in thread that could act as an easily removable attachment point for the dust catchment container.
This, coupled with some PVC fittings and some flexible hose, resulted in a project that was simple, cheap, compact and highly modifiable. Suction is provided by an old vacuum cleaner.
Obligatory disclaimer: I don't take responsibility if you hurt yourself or destroy anything making this. This design probably won't compete with any commercial grade dust extractor and wont provide the equivalent performance. It is not a substitute for a good mask or respirator either. Always observe safe practices when in a workshop environment.