DIY CNC Dust Collection Cyclone Separator 10

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Owning a CNC machine means that you must inevitably find ways of dealing with the endless stream of dust that is created when cutting material. This dust can easily be controlled with the use of a shop vac. The downside, however, is that the dust filter inside the shop vac can only handle a limited amount of the stuff before it is overwhelmed and has to be cleaned to regain good suction. This is where adding a cyclone dust separation system can make your life much easier.

With such a system, most of the dust never even makes it to the shop vac’s filter because it is collected in a separate container located before the shop vac. This container also adds the advantage of making the task of emptying out the collected dust a lot easier.

I’ve seen several of these systems scattered across the web. The commercial versions similar to the one on this page range from around $20 to $100, and some of the DIY versions I found looked like they would take more effort than I felt like putting in.

I finally ended up just designing something from scratch. It turned out to be really simple to make. And guess what, it actually works!

Here is a top view of my DIY dust collection cyclone separator. The dust filled air enters through the shop vac hose on the right. It then spins around in a cyclone. Because it’s heavier, the dust ends up in the bottom of the bucket while the now largely dust free air continues out the the left tube to the shop vac.

To make this dust collection system, I started out with a lid from a drywall mud bucket and cut two 2.5″ holes with a hole saw. The input side (right) has a 90 degree PVC elbow attached to it. This is what helps create the cyclone. I used caulk to help seal around the PVC and hold it in place. I also used some weather stripping to seal around the shop vac hose.

The output side (left) consists of just the shop vac hose shoved down into the 2.5″ hole.



Here’s how much dust is in the bucket after several hours of operation. This bucket is deeper than your typical 5 gallon one. It’s somewhat hard to make out in the picture, but there is about 4″ of dust in the bucket.

Here’s a picture of the inside of the shop vac. Notice how there is hardly any dust in it. Also, keep in mind that my shop vac wasn’t exactly clean to begin with. It will be a very long time indeed before I have to empty it out.

I’ve been quite happy with this DIY CNC dust collection separator’s operation so far. It’s amazing how such a simple thing makes my life so much easier.

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10 thoughts on “DIY CNC Dust Collection Cyclone Separator

  • Gabriel Miller Post author

    I’m not sure. I’ve never had static electricity be too much of a problem.
    You might try adding some water in the bottom of the bucket since static electricity doesn’t build up quite so easily in moist environments.
    You might also try grounding the bucket to something metal, like a metal shelf perhaps?

  • Gary Tonini

    Hey great idea I did build one of these only problem I have is static electricity buildup in bucket any ideas on how to fix this ? Thanks Gary

  • Ben

    Neat execution. One thing to keep in mind is that a shop vac has a terrible filter on it. It lets most of the super fine dust (the stuff that you can’t really see but what is the most dangerous particulate matter) through without any intervention at all. If the filters were any good at collecting this dust, they would clog up in a matter of minutes. Even the high end filters apparently have difficulty with this stuff. Most dust collection cyclones (and especially home-built ones) will only separate out the heavy stuff, allowing the super fine stuff into the vac which then massively redistributes it throughout your shop (and your lungs and throughout your house if your shop is attached). Bill Pentz, who is an expert at dust collection, calls these and most dust collectors dust pumps for this reason.

    A rather simple solution to all of that would be to hook the exhaust of your vac to a tube that runs out of the house. That way the super-fine dust is expelled away from your lungs and into the atmosphere where it quickly becomes diluted and eventually trapped in the moisture of the day.

    Again, I think this is a really cool thing you built, but I just wanted to point out one feature that would make it safer.

    • Gabriel Miller Post author

      That’s a good idea. I hadn’t really realized that some dust was able to get through the filter, but it does make perfect sense. It would be easy to vent it outside too.

  • Colton

    Is the amount of suction or air flow reduced in the hose from the bucket to the CNC (or whatever you are collecting dust from)? This may be a stupid question, as I do not have any experience with or knowledge of dust collectors. I really like this idea and am planning on trying it out, thanks for the detailed site.

    • Gabriel Miller Post author

      The suction seems to the same after going through the bucket to me. I’m sure it is probably reduced some, but not so much that I can really notice. Of course, holding my hand up to the end of the hose to see how strong the suction is isn’t really the most scientific way of measuring it. :)

  • Tony Laud

    The draw is in the center is to simulate the low pressure system in a tornado. The cyclone effect is created by the suction air rotating around the center low-pressure vortex. In other words the 90 degree angle in the PVC fitting is a set-up to guide the air around the perimeter of the container , rotating the air-mass and forming the cyclone effect. The only improvement to this system could be the addition of a Thien plate, (in such a small space it might have a minimal effect though). Tony

  • Joe Torre

    I love your website and everything your helping us all out with, but I’m curious:
    Why didn’t you locate the suction port in the center of the lid (and the cyclone)?
    I was going to make one of these myself, and may try that position.

    • Gabriel Miller Post author

      Hi Joe,
      I really don’t know for sure which is better. I think either way would probably work though because I’ve seen commercial designs for each version.

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