Dust seperator for the CNC

I have a love/hate relationship with MDF.  It sure machines nice, and paints well if you seal it with watered down glue first.  But the DUST!  My 5hp shopvac has a steady reduction in suction as the filter clogs up.  It’s capacity is noticably diminished only 1/2 way into a machine run.  I have been looking at Bill Pentz’ cyclone page for a long time, with dreams of building one.  Sourcing of the metal, room in the garage, and downright dislike for sheetmetal cuts has dissuaded me from going down that route (thus far!).  I recently came across the ‘Thien Separator’ which in concept seemed like a good comprimise.  Didn’t look like it would take long to make, could be adapted to a shopvac/5 gal bucket and had nominal sheet metal work.

So, with that in mind grabbed a bucket, a caliper, and my mouse and drew something up.  Initial design didn’t take long to get drawn, and over a couple of days I made minor tweaks until I got a chance to run it on the machine.

Clogged the shopvac BTW.

So you can see the pieces outlined, from the first run.  Piece on the left is the bottom of the bottom.  You can see the 120 degree cutout, the bucket groove, holes for bolts, and the profile cut.  On the right is the bottom of the top.  Groove for the sheet metal, and a hole for the outlet to the vaccuum.  Along the top are the risers which mount the incoming line (it’ll make more sense in a later pic) and an aborted ring made to support the outlet.  I hit the y-axis limit switch, and had to redo that later.

I pulled the pieces and cleaned them up.  I then also machined a 1/8 groove in the top of the bottom piece which was needed to receive the sheet metal (not pictured).  Below you will see a picture of the bottom sitting on the bucket.  You can see where the incoming material will circle around, and fall into the slot – landing in the bucket.  At least thats the plan!

For the sheet metal, i picked up a roll of 10″ galvanized flashing.  I trimmed it down to 8.4″ (8″ + two 1/4″ slots + wiggle room).  It was pretty thin (not sure what gauge) so I cut two pieces and doubled them up.

Pretty straightforward assembly from here.  Work the metal into the 1/8″ slots, sandwich the top and bottom.  Tighten the threaded rod.  Insert the inlet blocks, and glue them in.  Silicone around the edges.

Here is a picture of the final product.  I am going to test drive it with a garbage can liner in the bucket, as it would make disposal real slick.  Right now the seperator sits on the bucket with a friction fit, and with the vaccuum on i don’t detect any leaks.  I will post updates on effectiveness after my next CNC run, but a quick cleanup of the dust on the floor, shows most of it ends up in the pail!

EDIT:

Ran the system on both the CNC and the Tablesaw today, and the seperator worked swimmingly!  Nothing of note in the shopvac, about 4 inches of dust/shavings in the bucket!

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