Harbor Freight Dust Collector Conversion


I saw the idea of converting the standard Harbor Freight Dust Collector with a separator and Thien Baffle on a mobile cart from these two members of Lumberjocks.com. I want to first begin by thanking Cory and Bert for sharing their ideas and creativity here. These two projects inspired me to make my own version.
Cory http://lumberjocks.com/projects/29578
b2rtch http://lumberjocks.com/topics/46668

I used this DC as it came out of the box for a couple months before I decided to make the changes. The original mobile base worked great but added to height of the collector. My basement workshop has low headroom and the ability to wheel it around was limited with obstructions like lighting, pipes, and duct work. Even though I’m a weekend warrior woodworker, I found the collection bag filled quickly and was cumbersome to remove and put back on. But, overall I thought this dust collector was a definite improvement over using my shop vacuum set up that I’ve been accustomed to and sick of dealing with for so long.

One of the priorities in a design change was to have a mobile base that would keep the DC low to the floor. So, where could I go wrong if I used a Harbor Freight Mobile Base for my Harbor Freight Dust Collector? I wanted a separator with a Thien Baffle to the capture the chips and keep most from entering the collector bag. I also wanted to upgrade the 5 micron bag to a Wynn Cartridge Filter to reduce dust in the air and my lungs, and have an added bonus of lowering the height of the collector.

And now after a couple more months of use, but this time with the upgrades, I am quite pleased and think this was worth the money and time. This mobile DC will probably remain parked in a corner of my workshop for most of its use, but steers around pretty good clearing all the obstructions as I move it around when I need it to. The motor and impeller housing support post assembly is very solid. The trash can separator with Thien Baffle performs great. Having the remote is just plain convenient. The Wynn Filter Cartridge improved air quality for the health of the workshop and myself.

I did a run of 4” S&D pipe 15 feet long to reach my table saw. But for the other tools, they are on mobile bases as well and I can maneuver them from against the wall to out in the middle of floor and close to the DC. For all that I purchased Rockler Dust Right Fittings for the tools and a long enough Dust Right Hose to reach them. I thought I’d might buy the Dust Right Storage Rack and Floor Sweep Kit but had sticker shock when I seen the amount they added to the bill with all the Dust Right Fittings and Hose. I came up with a cheap alternative using PVC and a hose spring clip to contain the Dust Right Hose and all that is explained in detail in a photo below. And the other cheap alternative that works great is the floor sweep I made up from the wands and floor nozzle I saved from a burned out shop vacuum. I took a 2-1/2” to 4” Dust Right Fitting and fitted to the end of the wand and used a hose spring clip to contain it on the cart. You can see that in the project post photos.

I took the provided dimensions of Cory’s and Bert’s mobile carts, the ideas I had, and winged it from there. Pretty straight forward build with everything mechanically fastened with a combination of simple joinery, glue, lag screws, carriage bolts, hex bolts, and screws. I didn’t prep the lumber much at all. At the big box store I sorted through all the crooked until I found nice straight pieces. I did however apply a finish of a home brew wipe on poly.

The picture below shows the cart without the separator, hose, and floor sweep for clarity. That short piece of PVC and hose spring clip works great to contain the Dust Right Hose when not in use. I cut a wooden disc that is the same diameter as the inside of a repair coupling and screwed to the plywood, and then the repair coupling is screwed to the disc. The PVC fits into the coupling and is topped with a knockout cap to keep dust and debris from falling down inside. The Long Range Switch mounted nicely between the 4×4’s with the supplied hardware. The power cord for the Harbor Freight DC tucks away in behind the motor bracket while the Long Range Switch power cord has a cord wrap for when I move the cart around.

The picture below shows the Peak Post Anchors. I painted them black. They are mounted to the 4×4’s with supplied hardware and that assembly is secured to the double layer of ¾” plywood with carriage bolts. Also, you can see how I attached the double layer of ¾” plywood to the mobile base. I drilled holes in the metal corners of the mobile base with corresponding holes in the plywood and fastened with hex bolts. You may notice that the post anchors are mounted off center from the cart. This was done to allow room for the 4” Dust Right Hose and the PVC to support it.

The picture below shows how the DC motor bracket is mounted to the 4×4 posts. There’s spacers between the 4×4’s and the motor mounting bracket. The spacers are 2×4’s planed down to 1-3/8” to align the center of the impeller inlet with the center of the garbage can lid inlet. The spacers are lagged into the 4×4’s. The machine thread to wood thread dowels go through the spacers directly into the 4×4’s. Short lag bolts hold the impeller housing brackets to the spacer.

In the picture below shows the riser for the collection bag, donut ring, and Wynn Cartridge Filter. Because I wanted a good amount of clearance for the garbage can separator I needed this riser to raise everything 3-1/4”. The riser is made from 1×4’s with mitered corners. Screw cleats fasten the riser to the cart from the inside and screw cleats fasten the single layer of AC plywood from the outside. Lags were used to fasten the legs.

31 Gallon Trash Can Separator With Thien Baffle

Along with the information I gathered from Cory’s and Bert’s projects, I also found everything I needed to make my version here

This separator with the Thien Baffle performs great and is super easy to access and empty compared to the collection bag. I’ve emptied the trash can a handful of times in the couple months since making the upgrades. With only about a couple cup fulls of dust in the collection bag, I don’t expect to empty it any time soon. I seen performance gains with the new motor and impeller configuration and using the Wynn Cartridge Filter, but some if not most of that was lost when I added the separator. With no way to measure this accurately, I will play it safe and say the collector performance gains and loses factored together is about a wash. From what I’ve read, my situation is par with others who did the same type of upgrade.

In the two photos below you can see what I did to get started. After cutting 4” holes the integrity of the garbage can lid weakened, so I beefed it up with a MDF insert. The insert fits the contour and recessed nicely in the lid. The insert is fastened to the lid with Quick Grab adhesive and pan head screws. While it adds a little weight, it is really ridged and provided a flat surface to mount the elbow and Thien Baffle.

I didn’t want a sharp bend in the Dust Right Hose as seen with Cory’s and Bert’s versions. In the photo below shows that I chose to build the separator with 2 opposing elbows. I used a street elbow down inside the can. The “shoulder” of the street elbow rests in a bead of silicone on the MDF insert as it passes through the opening. The elbow on top is a standard elbow that I scribed and cut to fit the contour of the lid. I secured it with a pan head screw and ran a bead of silicon sealing it to the lid.

The 5” to 4” reducer didn’t extend into the center area of the baffle far enough. I read on the Thien website that this inlet needs to extend into the baffle area by a ratio of ½ the diameter of the elbow. The photo below shows I extended this to two inches using a 4” long piece of S&D pipe. I first fit the reducer into the opening in the garbage can lid and tacked it into place with hot melt glue. I then put a bead of silicon on the rim on one end of the S&D, flipped the garbage can lid over to fit the S&D through the opening in the MDF insert and into the reducer to adhere the two together. And finally, I ran a bead of silicon to seal the S&D to the MDF insert and the reducer to the garbage can lid.

The Thien Baffle secures to the MDF insert with ½” dowels. The dowels connect into holes in the insert and baffle with glue. Before I just grabbed a drill and drilled the holes with a ½” bit I found that the dowel from the big box store was slightly undersized. I drilled a test hole on scrap with a 15/32nd drill bit and it was a perfect size for a tight fit. The large diameter of the baffle begins just behind the end of the street elbow. There is about 1” clearance in between the bottom of the street elbow and the baffle so chips can pass underneath without issue.

In the picture below, going left to right, shows the connection of the Dust Right Hose to the separator. First is a Dust Right Swivel connected to a 3” DWV to 4” S&D adapter. Connecting the adapter to the elbow is a piece of S&D pipe cut 4” long. The fittings are secured with screws and a hose clamp. The 5” hose that connects to the impeller is a piece I cut from the hose that came with the Harbor Freight collector. I swapped out the hose clamps that came with the collector with better ones.

In the photo below is all the fitting I needed to put this all together.

Materials List

Harbor Freight Dust Collector
Harbor Freight Mobile Base
Lumber listed below is rough size unless noted in parenthesis
1-4’ x 8’ sheet 3/4” AC Plywood (mobile cart platform and riser)
2-2 × 2 × 6’ SPF stud grade (planed to 1-1/4” x 1-1/4” for Harbor Freight Mobile Base)
1-1 x4 x 8’ SPF #2 and better (ripped to 3-1/4” for riser)
2-3/4 × 3/4 × 8’ scrap bin material (screw cleats for riser)
2- 4 x4 x 5’ SPF #2 and better (DC motor and impeller housing support post assembly)
2-2 × 4 × 16” SPF stud grade (spacer planed down to 1-3/8” for DC motor and impeller housing support post assembly)
1-2 x6 x 2’ SPF stud grade (also a 1/2”x 5-1/2” x 1’ scrap material as a spacer for the DC motor and impeller housing support post assembly)
1-1 × 3 × 16” pine from scrap bin (for cord wrap)
2- Peak Post Anchors (DC motor and impeller housing support post assembly)
1-3” x2’ PVC (restraint for 4” Rockler Dust Right Collection Hose – cut to 16” long)
1-3” PVC Repair Coupling and a scrap piece of wood cut into a disc (restraint for 4” Rockler Dust Right Collection Hose)
1-3”’ PVC Knockout Test Cap (restraint for 4” Rockler Dust Right Collection Hose)
2-4” Dust Collection Hose Spring Clip (restraint for 4” Rockler Dust Right Collection Hose and Floor Sweep)
Shop vacuum wands (2) and floor nozzle (1)
PSI 110 Volt Long Range Dust Collector Switch With Remote
Wynn 35A274BLOL 80/20 Blend Cartridge Filter
3/4”, 1-1/4”, 2” and 2-1/2” drywall screws (DC Mobile Cart)
5/16” x 1”, 2-1/2”, 3-1/2”, and 4-1/2” lags with washers (DC Mobile Cart)
1/4” x 2-1/2” carriage bolts washers and nuts (DC Mobile Cart)
5/16” x 2-1/2” hex bolts washers and nuts (DC Mobile Cart)
4” machine thread to wood thread dowels with washers and nuts (DC Mobile Cart)
Behrens 31 Gallon Galvanized Trash Can
4” Rockler Dust Right Collection Hose – 3’ Compressed Expands to 21’
4” Rockler Dust Right Multi Port Quick Release Kit
4” Rockler Dust Right Swivel
1/2”x 2’x4’ MDF (Separator and Thien Baffle)
1/4” x 2’ x 2’ hardboard (Separator and Thien Baffle)
1/2” x 2’ poplar dowel rod (Separator and Thien Baffle)
2- pieces of 4” S&D pipe 4” long (Separator and Thien Baffle)
1- 3” PVC DWV to 4” S&D adapter (Separator and Thien Baffle)
1- 4” S&D standard elbow (Separator and Thien Baffle)
1- 4” S&D street elbow (Separator and Thien Baffle)
1- 5” to 4” dust collection hose reducer (Separator and Thien Baffle)
1-5” dust hose (cut off from hose the came with the HF dust collector) (Separator and Thien Baffle)
2- 5” hose clamps (Separator and Thien Baffle)
3/8” and 1/2” pan head screws (Separator and Thien Baffle)
Clear Silicon (Separator and Thien Baffle)
Quick Grab Adhesive (Separator and Thien Baffle)
Hot Melt Glue (Separator and Thien Baffle)

Measure "at least" twice and cut once


Nice job! I will get around to doing this, eventually. I do have a Wynn filter and Thien setup, but really want to rotate the motor and shorten the hoses. Love the way you created your flex hose storage. That is a keeper.


Thanks Mike !…Appreciate the compliment !

Measure "at least" twice and cut once

Thank you so much forgiving me some of the credit for your beautiful realization, you are a real mensch


Frenchy…..Took me a second to realize who you were. Your avatar and name are different than what I am used to seeing. Thanks Bert for the compliment and again thanks for sharing you DC makeover on Lumberjocks.

Measure "at least" twice and cut once

whitebeast88…Thanks for the compliment !

Measure "at least" twice and cut once

Impressive build.

your work is neat.

Abbas, Castro Valley, CA

lanwater….thanks for the compliment

Measure "at least" twice and cut once

Very nice work and extremely impressive description !

John in Belgrave Ontario Canada

Thanks John ! Compliment is appreciated !

Measure "at least" twice and cut once

Nice silk purse. Gads, having a good dust extractor makes such a difference in the comfort of the shop.

I rarely turn on the vacuum anymore, since the collectors do a good job of grabbing everything (I used a four inch, green pipe with a handle on it). The separator is so nice. I used to cringe every time a screw, or even an errant tool went flying through the impellers.

Thanks Kelly….Having a DC makes life easier

Measure "at least" twice and cut once

Very well thought out design,great job.

woodworking classes, custom furniture maker

Thanks for the compliment Jim !

Measure "at least" twice and cut once