Harbor Freight Dust Collector 2 Stage Cyclone Modification


I’ve been using a cyclone on my shop vac for a few years now and I’ve always been happy with it. Even though I’ve liked it, there’s always those times where you start planing a bunch of boards and it gets filled up way too fast. Plus the air flow just wasn’t there to collect from some of my larger tools efficiently. After doing some research and counting my pennies, I decided to go for the Harbor Freight dust collector and planned on modifying it into a two stage cyclone down the road. Only a couple of months after purchasing the DC, I started purchasing bits and pieces of what I wanted in my final setup.
After slowly collecting part after part for my two stage cyclone collector, I had all of the following pieces:

20150711_180111My original plan and design was to mount it on the wall and then suspend the filter and overflow bag from the ceiling. After remembering how heavy that motor is and that one day I’m going to move this to my future shop, I decided to go for the somewhat more portable design with a full frame around it. Plus if I want some cabinet doors in the front, it wouldn’t be a problem.

2015-07-22-2B20_24_48-Windows-2BMedia-2BPlayerI built the middle and bottom platforms that holds the 30 gal drum and the cyclone based on the size of the space between the wall and my garage door. Plus that almost exactly the same size as my scrap plywood and it fit the drum and cyclone perfectly. I modified the lid to the 30 gal drum by adding a 5″ duct flange. Then using the 5″ hose that came with the DC, I cut off about 8″ to use between the cyclone and the drum to allow easy removal of the drum for emptying.
When working on the different connections, you’ll want to
20150711_180126make sure you get a good seal. I’m sure you could probably pickup some weather-stripping or just silicone it but I had some thick rubber lying around so why not make a rubber gasket. I cut the hole in the middle platform making sure to align it so the motor would connect to the mounting board after being placed on top of the cyclone.
20150711_19011020150711_184054After all of the platforms were built, holes cut, flanges and seals were done, I was on the home stretch of this build. I used the rest of the 2x4s and connected everything together making sure there was enough room to provide enough flex in the hose below the cyclone and the waist bin.
2015-07-22-2B20_26_28-Windows-2BMedia-2BPlayerThis motor is heavy and I don’t want to run any risk of it coming lose, so I put as many screws into the mounting board as possible. I rummaged through my nuts and bolts and found something with large washers that would provide a lot of support.
2015-07-22-2B20_27_59-Windows-2BMedia-2BPlayerI planned on shortening the bag to the height of the cyclone, the supports for the filter and overflow bag also had to be shortened. I just marked them and cut them off with my grinder. Then using my large vise, I bent them back into the original shape. Then had to promptly add risers to the bottom since I made them all a 3/8″ too short.


2015-07-22-2B20_28_39-Windows-2BMedia-2BPlayerThis new canister filter greatly increases airflow and does a much better job at filtering out small particulates that make it past the cyclone. The old filter went over the whole filter frame and clamped on. This one is a little different but almost easier to install. The new canister filter is connected using a few provided turnbuckles between the support frame and internal rim of the canister.
After sealing up a couple of the seams with metal foil tape and hooking up my remote power switch, I was done. It took me nearly an entire Saturday but I finally had a two stage dust collector. Now to figure out ducting around my garage so I can get rid of this temporary flex hose.
20150711_141536Here’s two examples of why it’s a good idea to do this modification. The 5 micron bag doesn’t filter out fine dust and it can get clogged pretty fast reducing airflow after only a short period of time. Without the cyclone in front of the motor to remove most of the sawdust and chips, you can really damage your impeller blades. In the short time that I’ve had this dust collector, I can only recall a few times where a larger chip fell down into my table saw and got sucked in. 20150711_142809Each time you would hear the chip go round and round in the impeller casing causing damage to the walls and impeller blades. You can see in the picture above that only two of my blades were still in near perfect condition. I had to do my best to straighten and repair the rest.


32 Comments on Harbor Freight Dust Collector 2 Stage Cyclone Modification

  1. Hi! I’m on the process of modifying my HF DC also. Straight out of the box, I built a separator out of a metal garbage can with a 4″ 90 and a straight peice of pipe running thru the lid to create the “cyclone” action. But with this method if really noticed a drop in suction. I’d really like to get a super dust deputy but only if the suction will stay the same as the “factory” setup or increase it. Can you shed some advice and experience on this issue. I’m fairly new to dust collection. I’ve watched your videos and love your setup, just want to know how it performs. Thanks, Marc

    • Hey Marc, I actually just answered this same question on Facebook. I would expect that the cyclone would also slightly decrease the suction but as long as everything was properly sealed it shouldn’t be too noticeable. However, what a properly running cyclone will get you is a clean filter which will keep your suction consistent where the standard out of the box HF DC quickly clogs. I can’t really say how much if any the cyclone actually decreased the suction because I also added a Wynn canister filter at the same time which greatly increased my suction over the factory provided bag filter.

      Hope this helps!

  2. Nice set up, have been considering something to control dust in the shop, but am concerned about the amount of noise a system such as yours will create. Any idea what the noise level from your unit is.

    • The noise level isn’t too bad compared to the tools I’m using to collect dust from but I also don’t run it unless I’m running those tools. In my future shop, I plan on putting in a separate closet just for the dust collector and compressor so I can carry on a normal conversation while these tools are on.

  3. Hi,
    Where did you get your reducers from?
    I picked up a 6″ to 5″ and a 5″ to 4″ from Lowes along with a 6″ coupler, and none of them fit right. I have an identical setup to what you have here.

    Where did you find the one you’re using here?

    Love your work by the way.

    • I got the metal ducting reducers from Oneida when I ordered my Dust Deputy. Sad to say that I had a difficult time with mine too… I ended up drilling out some rivets on the big adapter so it would fit. A little foil tape and everything was good to go.

      I would have thought the adapters that Oneida sells would fit their own equipment. Looking into it a little more, this diagram shows that the 6-5″ reducer should be crimped but the part they sell isn’t. Perhaps we should be crimping our own ducts? Maybe some duct crimpers would help? Wish I would have had a pair during my install but who knows…

      I did ask Oneida why their parts don’t match. (Approximately 3 minutes ago on Twitter)


      • Thanks. I eventually got the 6″ to 5″ to work by crimping it in and then taping it up like crazy. Waiting on another hose to arrive, then I can set it all up and test for leaks.

        Thanks for the reply!

  4. I’m building a similar setup, and found a cheap alternative to the two 5″ flanges.

    I picked up a Woodstock 5″ Blast Gate, which is made of two separate plastic pieces that can be popped apart into a pair of flanges. $12.15 on Amazon.

  5. I’ve been reading many columns on modifying the Harbor Freight Dust Collector, and this is the most simple, straight forward and rational plan I’ve come across. Thanks, I will put it in action soon.
    However the fiber drum you link to is no longer available. In looking for a substitute what features do I need to include? Is the lever lock top a necessity? What dimensions are important? Is there a substitute you know of?
    Also, what remote start do you like?

    • That sucks that they currently out stock. The biggest thing you’ll want to look for in a replacement drum is that it is capable of getting a good seal. You ask if the locking lever is a necessity I would say that it may not be required but in my opinion, it drastically improves the seal. The other thing you’ll want is strength. You could go with a rubbery/plastic garbage bin but the chance if it collapsing in oneself is fairly high. Here are some non-amazon links to similar fiber drums that you may be interested in. http://goo.gl/02tuEQ & http://goo.gl/E22eRt

      As for a remote, I use this cheap one from Amazon. This could also be found on My Tools page. It’s only rated for 13 amp and the HF DC says it’s 15 AMP but I’ve never had an issue and for that cheap price, I could buy a few if it ever stopped working.

  6. Hi Ty,

    This is definitely the nicest and most compact set up I’ve seen for the two stage Harbor freight and I ask that you allow me to duplicate it. Please excuse the request and if there is a set of plans that you sell I’d be more than willing to make the purchase. I didn’t see anything so please direct me to it if You do. If not maybe you can answer a few questions. What is the height and footprint of the stand. Over the last year or so I too have purchased all the necessary parts but my space is tight I think you’re set up just might be the answer I was looking for. If I may, what size are the plywood platforms that you use.

    • Hey Ray,
      You are more than welcome to duplicate this project. I don’t sell plans but I do have a SketchUp file available for download that should have all of the rough dimensions. I’ll try to remember to measure the entire thing when I get home but it’s it’s roughly 22x48x96-inches. If you need it to be a little shorter you could probably drop the entire thing by about 8″ by reducing the length of hose between the bottom of the cyclone and top of drum as well as using just a single piece of plywood on the bottom for the base instead of making a frame with a piece of plywood on it.

  7. Hi Ty,
    I am wanting to build a collection system like yours; it looks like you did an outstanding job on building it. Can you tell me what have you spent roughly to get it up and running? How is the performance of the system, like does it have enough suction power; can it handle a 12″ planer and table saw? The dust collector would be 17′ away from the equipment.
    I don’t want to spend the money and time putting it together if the system does not perform adequately.

    • Hey Darrell,

      I spent about $600 total and the most expensive thing was the filter with the cyclone and DC (with 20% off coupon) trailing closely behind.

      I had two 10′ hoses connecting mine to my table saw and 8″ jointer and never had an issue with collection. When using my 13″ planer, I only used 1 10′ length but that was more because of location. Just make sure all of the joints are sealed between all components to ensure the cyclone works properly and you maintain optimum power.

      Hope this helps.

      • thanks for the info Ty.Did you run the system before you installed the super dust deputy,I was told that the super dust deputy may decrease the suction of smaller dust collectors this is just here say.

    • Has anyone ever come up with a cheaper alternative to the Wynn filter? I’m sure they work great, but they are speedy. I have the 3 horse unit I want to convert over to two stage. So that means I would need 2 of the filters

  8. Anyway you can provide the dimensions of the frame (HxWxD)? I’m using your design to modify my HF system. Thanks for any help you can provide.

    • Hey Jason,
      It’s roughly 22x48x96-inches. If you need it to be a little shorter you could probably drop the entire thing by about 8″ by reducing the length of hose between the bottom of the cyclone and top of drum as well as using just a single piece of plywood on the bottom for the base instead of making a frame with a piece of plywood on it.

  9. I’m also in the misted of making my dust collection system. I noticed that someone asked about the loss of suction when adding the SDD, never saw a response. I’m venting mine outside not using a filter. I found a 30 gal plastic drum with a lid and clamp on band for my container. A guy (on Craigslist) in Chicago is selling them for $13.

  10. I just ran across this article as I have the same setup. I was looking for a way to shrink down the whole think. Thanks!!

  11. Hi! Thanks. This is great—I’ve begun collecting materials to do something similar using this post. I managed to find a great deal on a *plastic* 30gal drum, but I failed to realize that you also use one to replace the overflow bag. I did order a Wynn nano cartridge, but I’m wondering if I can get away with using the HF overflow bag instead of an additional drum. If not why? And, is there a reason to go with fiber over plastic, or that simply a function of availability?

  12. Do you find that the middle platform (that the Super Dust Deputy is attached to) is really necessary. If the Dust Deputy is attached to the lid of the canister, it isn’t heavy and when the can is removed there shouldn’t be much downward pull. Your thoughts?

    • Not particularly “necessary” but it’s a decent shelf for random crap… I ended up removing the bottom platform and building a small riser for the bin. That gave me more room for storage next to it.

  13. Hi trmoser, I am wondering to see the project you build. It’s really an excellent Harbor Freight Dust Collector I have been seen. And I’m surprised to know that you didn’t develop this superior dust collecting technology just for sale. Instead, you help others to build the same thing on their own. Thank you so much for this exciting works, and I hope we will get such kind in the future continuously.

  14. Have you had any issues with the drum collapsing? I’m working with a similar concept as yours, but mine is using a shop vac and I built my own cyclone in the lid of the fiber drum. I’ve only ran it for a short time and am now having issues with the drum collapsing.

    • I haven’t had any issues with this 30 gallon drum collapsing but on my other system where I used a shop-vac and a 5 gallon bucket it did end up collapsing after some time. I still use it, just with a new bucket and it’s been ok.

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