I created an upright dust filter based on a similar concept from YouTube poster Ron Calverley. It can filter air at 1 or all 3 levels at once. It's a double filter design for each level. The blanks on the top of the cabinet would be used to block 1 or 2 of the 3 openings, creating a much larger intake pressure. I put 1/2" hardware cloth inside the filters to prevent a filter from being sucked in.
There's some rabbeting involved in this concept to minimize visible screws. HOWEVER, if you just did square edges and screws, the project would take 1/4 of the time.
YouTube posters tell you old furnace blower motors are a dime a dozen.. Not True unless you have a residential HVAC friend. Decent 3 speed ones (used) start at around $80. The 3 switches on the side would be two 3-Way and one 2-Way switches. You can only run power to one speed at a time. I haven't wired mine as of 12/28/16, but there's a way to wire those three switches to accomplish this.
I would say low budget on this project is around $250. So knowing that, it could be worth it to look at Jet / Grizzly / Delta ones first.
#blower #collector #dust #filter #shop #woodshop