3D Printed Cyclone for Fein Shop Vac




Introduction: 3D Printed Cyclone for Fein Shop Vac

About: Part time woodworker, 3D printer.

I like to do woodworking and I recently bought a Fein shop vac to replace a Craftsman that I had had for 20 years. The Craftsman was still working, but it was deafening, at about 98 dB. The Fein is about as about as loud as the vacuum that we use in the house, closer to 70 dB. The Fein has more suction that the Craftsman, but it can’t hold as much waste, and it uses $7 bags. After my last woodworking project, I decided that I should get a cyclone separator for it, to save money on the bags. I looked at several options, and I came across the separator that Festool offers for their shop vac. It is integrated with their vac, fitting neatly on top of it. I decided that, that was the way to go.

There are basically two types of ‘cyclones’ used for separators: Cone and Spool. Most commercial offerings are Cone designs, so I started there. Below is an early model that I made, which uses a Cone design.

This design would have probably worked fine as a separator, but I had a number of issues with it:

· It was tall! And the return hose back to the vac, coming out the top, would make it even taller.

· The bottom of the cone limited the tray space available on the top for tools.

· It raised the point where the hose would attach very high, making it more likely to tip over the vac over if I pulled on the hose very hard.

· And it was sort of ugly.

I settled on the Spool based design above, which isn’t quite as efficient a separator, but it’s a lot more compact and addressed all of the issues above. I couldn’t find any good separation efficiency comparisons between Cone and Spool based designs, but I suspect that that efficiency difference is not enough to worry about. The more important part is holding a good vacuum. You want to eliminate, or at least minimize any vacuum leaks. The spool design works very well. If you watch the video, I was almost able to fill the box in 30 seconds.

This design uses big parts, which take a lot of time and filament to print. My overall print was about 250 hours. I quartered the main parts of the body to fit on my print bed, and each quarter of the Top took about 40 hours. And it took most of 3 2kg spools of filament to print, but that did include some reprints.

The STL files and complete documentation are available at https://www.thingiverse.com/thing:4206700

And a video of it working is available here:


Below are the parts that I used for the Separator. If I bought them on the web for this project, I included the link I used, but some of the parts I found in my garage, left over from other projects.

· (10) M3x30mm 0.5mm Pitch Bolts Socket Cap Head Hex Key Screws


· (10) uxcell M3x5.5mmx2mm Zinc Plated Square Nuts


· 2-1/2 in. x 7 ft. Dual-Flex Tug-A-Long Locking Vacuum Hose for RIDGID Wet/Dry Shop Vacuums (part number LA2520)


There are several other vendors (e.g. Craftsman and Workshop on Amazon) that offer the a compatible 2-1/2-Inch Locking Wet Dry Vac Hose for Wet Dry Shop Vacuums, but in longer lengths, which makes it more expensive.

· Clear acrylic plastic sheet.

4 pieces are needed to make a box with 268mm wide x228mm deep outside dimensions. I cut all the pieces about 300mm long, which sets the height of the box. You can make it as tall as you want. Just remember that the taller it is, the easier it is to pull it over if you yank on the hose. The acrylic that I used was 5.8 mm thick, so I used the following dimensions for the acrylic sheets. Depending on the thickness of the acrylic sheets that you use, you will have to adjust the width of the sides.

- (2) Front and back 268x300mm

- (2) Sides 216.4x300mm

- (3m) 3mm O-ring cord, Seal for Spool, Top, and Box.

- (2+) 2Kg spools black Hatchbox PLA Filament.

If you have it, I would suggest printing the parts in either PETG or ABS. So if it’s left in the sun, they are less likely to warp.

· (small amount) Ninja Flex black TPU Filament

For Elbow Seals.

· (1) Husky 16 ft.x 1-1/4 endless loop ratchet tie down


This Husky tie down is over-kill, but I it was laying around. Any ratchet tie down with a flat nylon strap width less than 33mm will work. The hooks need to fit over a least a 20mm shaft.

· (6) #8 x 1/2in Pan Head sheet metal screws

Step 1: Other Hose Adapters

I also included two STL files for adapters for the Fein hose that designed when I first got the vac, which allow me to connect all my old Craftsman vac 1.25 inch ID attachments to it.

The first shows the Fein supplied hose adapter (black and orange) that includes an adjustable vent (orange) which allows you to reduce the vacuum. Attached to it is my Fein Hose adapter 1 (white and in the second figure), which slides onto the Fein adapter.

The Fein/Adapter 1 combination was rather bulky, and I never used the vent, so I designed the Fein Hose adapter 2 (3rd figure), which clips onto the end of the Fein hose, and replaces the two parts in the first figure.

Step 2: Components

This images identifies the various components, and how they are assembled. The component names in the Figure match the prefixes of the associated STL file names.

The Dust Extractor consists of 5 major components: Main Body, Upper Elbow, Rigid Adapter, and the Hook Mounts.

Step 3: Main Body

This figure illustrates the components of the Main Body. The component names in the Figure match the prefixes of the associated STL file names.

If Your Print Bed Is Too Small

I included STLs for the Top, Base and Cover parts (Fein Top.STL, Fein Base.STL, and Fein Cover.STL). However they were too large to print as a single part with my printer, so I quartered them each into 4 STLs (i.e. RF, RR, LR, and LF STL files for the respective parts) before I printed them.

To assemble the quartered prints, I placed some 220 sand paper on flat surface (I used the top of my table saw) and sanded the sides of the parts that were going to mate until I had removed most of the high spots. It doesn’t have to be fully sanded, because the solvent will melt the plastic and fill small (e.g. < 0.5mm) gaps, when you attach them together. I first glued the right and left pieces together. Then sanded the sides that would mate a little more to make them flat, and glued the fronts to the back. To fill any gaps, I ran a couple of beads of solvent over them, until I couldn’t see any light through them.

As I glued each of the quartered parts together, I would align the parts, press them together, then press them flat against the flat surface of my table saw.

For the Cover and the Base parts, I placed them bottom facing down to flatten them.

For the Top parts, I turned them upside down before I pressed them flat, because I wanted a flat surface for when I attached the Cover.

Step 4: Cyclone Core

I included an STL for the Cyclone Core (Cyclone Core.STL), but it was also too big to for my print bed. I split it into 3 STLs, so that I could print it, and so I wouldn’t have to use supports: Cyclone Core Top Left.STL, Cyclone Core Top Right.STL, and Cyclone Core Base.STL. Like the quartered parts of the Top, sand the surfaces of the Right and Left Top sides to take down the high points before gluing them together. I didn’t need to sand anything before gluing the Core Top to the Core Base.

Step 5: Acrylic Box

Once all the quartered parts were glued together, I cut the acrylic plastic and fitted the Box to the Base. I had a snug fit when I pressed them into the Base, and used a strap clamp to hold the pieces together at the top. Once I had all the sides positioned, I ran a bead of solvent down the 4 corners and around the bottom on the inside of the Box.

After the side solvent dried, I ran some more solvent around the outside joint between the acrylic panels and the Base. I did this a couple of times, until I saw that I had sealed all the parts together.

When you cut the acrylic they will have saw marks (scratches) on the edges. If you have a good blade on your saw, the saw marks will be minimal and the solvent will cleanly bond the pieces at the corners. If you don’t, you may have to run a file along the edges to smooth them.

If you have clean edges on the sides of the acrylic, then the scratches on the edges will disappear when you apply the solvent.

Flame Smoothing (optional)

You can ‘flame smooth’ the edges of front and back sheets to remove the saw marks. To flame smooth, simply take a propane torch, and wave the flame back and forth along the edge. The heat will melt the acrylic smooth. It happens sort of suddenly, so be ready to back off fast.

If you have any deep saw marks on the edges, file them out before you try to smooth them. I did not flame smooths edges that I glued.

Also, practice on some scraps first. It is easy to apply too much heat, and either bubble, deform or burn the acrylic.

Step 6: Hose Mount Assembly

The hose that comes with the Fein uses a tab, which slips into a slot on the front of the vac, and is turned clockwise about 40 degrees to lock the hose in place. As much as possible I used the same interface to mount the hoses.

There are 2 Hose Mount parts on the front of the Top. The Inlet is on the left and the Outlet is on the right. The Hose Mounts are not integrated into the Top, so they can be redesigned if you want to use the separator with a different vac or hoses. Which means that they need to be glued in.

The Outlet Hose Mount orientation is important!

In the Fein, the slot that the tab on the hose slips into is on the top of the mount (12:00). I used the same orientation when I glued the Inlet Hose Mount to the Top, see the figure below.

When I designed the ‘Elbow’ part (Hose Coupling Rt Angle.STL) I oriented the tab so the elbow would face up when inserted into the Fein house mount. If I want to use the same part for the Upper Elbow Assembly and have the elbow point in the right direction when it is inserted into the Outlet Hose Mount, then then the slot in the Outlet Hose Mount must be spun around to about the 6:30 position before gluing it in.

Step 7: Seals

There are 3 seals in the Top: Cover, Core, and Box. I used some 3mm O-Ring Cord to make the seals. O-Ring Cord can be bought on Ebay or Amazon.

Each seal fits in a 3mm wide 1.75mm deep slot. For each seal, I cut the end of the cord square, then laid the cord in the respective slot until it met the other end. I then cut the cord about 1mm longer. The ends of the O-Ring Cord can be superglued together to make an O-Ring, just make sure that both ends of the cord are square.

Step 8: Hook Mounts

I used a ratchet tie down to hold the main body to the shop vac. The nylon strap of the ratchet tie down goes through two slots in the Fein Cover and hangs down so the hooks on either end can attach to the Hook Mounts. To attach the Hook mounts I drilled 1/8 in holes in the top of the shop vac and used three #8 x 1/2in Pan Head sheet metal screws to attach each.

Be careful not to strip the screw holes by using too much torque on the screws.

Also when you use the ratchet to tighten the tie down to hold the Extractor on the vac, just snug it up so it doesn’t move. There’s no need to crush it.

Step 9: Rigid Hose Adapter

I picked up a Rigid “Tug-A-Long” Dual Flex Locking Hose (part number LA2520) to connect the separator to the vac. $22 at Home Depot. It comes with a variety of adapters.

The ends of the Rigid hose are designed to support different adapters. I used the ‘locking hose adapter’ with the ribs on one end, and cut the other end of the hose to length. To attach the cut off end of the hose to the Upper Elbow, I designed a ‘Rigid to Fein’ adapter (the Hose Coupling Rigid a and b.STLs), which uses the Fein style hose interface with the tab on one end, and an interface for the cut off end of the Rigid hose on the other. These files include a custom supports that I designed, which can be snapped out after printing.

Do not glue the halves together until you are ready to fit the connecting hose to length, which was the last thing I did.

The Hose Coupling Rigid adapter is designed to fit on the cut off end of the hose. It is in two parts, so they can glued together to firmly hold the end of the cut off end of the hose. See the figure. After applying the glue, I used some wood clamps to hold the two pieces tight together while they dried.

The component names in the Figure match the prefixes of the associated STL file names.

The Hose Coupling Seal was printed for the Fein end with TPU filament to make it flexible, and to seal the coupling. The seal does not need to be glued.

Step 10: Upper Elbow

The Upper Elbow uses the Fein style hose interface on both ends.

The Hose Coupling Seal was printed with TPU filament to make it flexible, and to seal the coupling. The seal does not need to be glued.

The orientation of the Hose Mount For Elbow slot doesn’t matter because the inter-connecting hose can rotate. Glue it to the Hose Coupling Rt Angle part.

I included a Hose Coupling Rt Angle.STL if you want print the elbow as a single part. But to avoid supports, I also include Hose Coupling Rt Angle a and b STL files, which can be glued together.

Step 11: Lower Elbow

The Lower Elbow uses the Fein style hose interface on one end, and a Rigid interface on the other. Again, the Hose Coupling Seal was printed with TPU filament to make it flexible, and to seal the coupling. The seal does not need to be glued.

I picked up a Rigid “Tug-A-Long” Dual Flex Locking Hose (part number LA2520) to connect the separator to the vac. It comes with a variety of adapters.

The orientation of the Hose Mount For Rigid Coupler doesn’t matter. Glue it to the Hose Coupling Rt Angle part.

Use the same Hose Coupling Rt Angle STLs for the Lower Elbow as the Upper Elbow, see above.

Step 12: STL Files

The STL files and complete documentation are also available at https://www.thingiverse.com/thing:4206700 or on

on Cult3D https://cults3d.com/en/3d-model/tool/fein-shop-vac...

Unless noted, I used a .2mm first layer and all other layers were 1.5mm.

I printed all the parts in PLA, but I would recommend using PETG or ABS for better temperature stability. If you can’t print the parts as one piece, then you will have to glue them. I know you can use Acetone to glue ABS, but I don’t know what can glue PETG.

The cover, top, and base are 310x270mm, which were too big to print as a single part on my printer, so I included quartered versions of the parts, which can be printed on a 155x135 bed.

Note Instructables has a 25MB file size limit, so some of the STL files for this project were too large to upload here. All the files are available on the Thingiverse or on the Cult3D sites.

I also set the Perimeter Vertical Shell count to 3, with a 10% infill. This should make them a little tougher for withstanding flying debris hitting them.

The Prusa printer has 4 options for supports:

· None

· Support on build plate only

· For support enforcers only

· Everywhere

You can't add a table to an Instructables Step. So in the attached Fein Dust Extractor Build Notes.pdf file there is a table (section 4) listing all the STL files and the print options that I used for them. Where there are question marks (???) in the table you are on your own, because I never printed those parts. You will have to decide for yourself, what the best option will be.

Note 1: I oriented the Hook Mount on the bed top optimize the surfaces of the part that were seen. See the figure. This resulted in wedge of support under the part, which was the side that attached to the vac, which no one would see.

Step 13: Some Notes on Gluing PLA…

I purchased the Bottle Applicator and Acrylic Cement (also called ‘Acrylic Solvent’) from Tap Plastics.

Bottle Applicator: https://www.tapplastics.com/product/supplies_tool...

Acrylic Cement:


The web page says that the Acrylic Cement is for INDUSTRIAL USE ONLY. This is because it is made up of Methylene Chloride (75-09-2), Trichloroethylene (79-01-6) and Methyl Methacrylate Monomer (80-62-6). ONLY use in a well ventilated area!!! Not only does it smell bad, but inhaling it can hurt you. So treat it with respect. Fortunately a little of it goes a long way, so the fumes from tiny drops are minimal. And don’t forget that it is also flammable!

This is probably the most volatile stuff I’ve ever used. When it comes to evaporation, it makes alcohol look like motor oil. There was an 1/8 inch of it in the bottom of the Bottle Applicator and it was gone the next day. And this was with the syringe top tightly screwed on, and the cap on it. Also, after 4 months of sitting the garage a 4 oz. container of the stuff that was almost full when I put it on the shelf, was empty! I found that the seal on the container is junk. After tightening as hard as I could, I could tip the container and the stuff would still drip out. My solution, which has worked pretty well, was to store the Cement container in a coffee can with a plastic cap. My theory was that, even with the leaky Cement container, the solvent vapor pressure would equalize inside the coffee can, and slow the evaporation process. But hold the coffee can away from you when you open it, otherwise you will get an eye watering whiff of the stuff.

To fill the Bottle Applicator, just squeeze some air out of it, then stick the syringe into the bottle. It takes a minute, but the stuff will be sucked into the bottle. I found that I never needed very much. An 1/8th of an inch in the bottle, will go a long way. Besides anything you leave in the applicator will evaporate away within a day.

The solvent leaves a little residue when it dries, which can clog the tube (syringe) of the Bottle Applicator. When you are done using it, squeeze the remaining solvent back into the can. And be sure to squeeze the bottle a couple of times to pump some air through the syringe to clear the solvent out of it. A couple of times (despite my best efforts) the syringe has clogged, and I had to heat the end with a torch to burn the residue out. The only problem with that is that the heat can anneal the syringe, and make it very easy to bend.

With all this said, a friend said that Acetone was just as effective a cement for PLA. Being a cheapskate, I will try it as soon as my current supply of Acrylic Cement is gone.


When using this Cement with the Bottle Applicator, its volatility comes into play. Normally you tip the Applicator and give it a squeeze to get a single drop of cement to come out, then relax your grip to cause an additional glue to be sucked back up the syringe. But because this stuff is so volatile, the heat from your fingers causes it to expand, so instead of a single drop, the expansion of the solvent inside the bottle causes it to start dripping immediately, even if you stop squeezing. This will flood your print with glue if the syringe is against it and make a mess. I found the best way to get a single drop was to hold the tip above a piece of cardboard, quickly tilt it to get a drop to come out, then tilt it back immediately, but no so much that the solvent reaches the end of the syringe inside the bottle. The ‘tilt back’ causes the drop of solvent to slide back to the working end of the syringe, without additional drips landing on your work. Note; this only works if there is just a little solvent in the bottle.

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    Tip 2 months ago

    You don't need that ratchet strap. Use a loop of bungee cord permanently fastened below, and just pull it up & over the separator module. The suction helps clamp the top on.
    Regarding fire-polishing acrylic plastic: DON'T! Looks great now, cracks & crazes later, unless you put the whole box in an annealing oven immediately after assembly. Acrylic plastic is hard to work with. I would use polycarbonate instead.
    Regarding the hose coming from the top & tipping: loop the hose down & secure the hose to the body low.


    Reply 2 months ago

    Thanks for the suggestions. And I guess polishing is overkill for something in the garage that literally collects dust. :-)


    Reply 2 months ago

    What I would do is to make 3 sides of the container out of aluminum, and the front only from clear plastic, to totally eliminate the need for any operations on the plastic other than cutting to size & drilling holes.


    Reply 2 months ago

    Sounds good! I will still be able to watch the hypnotic motion of the stuff swirling around in the chamber.


    2 months ago

    Acetone really only works on PLA if you heat it (which is tricky because it's also quite flammable). However Acetone works fantastically on ABS (which is very -very- temperature sensitive when printing). So it's a toss up of which is more of a hassle.


    Reply 2 months ago

    So what is the magic acetone temp for PLA?