Dust Collection Adapter (from Harbor Freight 2HP DC 2-into-1 "Y" to Super Dust Deputy 4/5's inlet port — 5" to 5"

When converting Harbor Frieght 2HP dust collector from 1-stage to 2-stage by adding a *Super Dust Deputy 4/5, you can use this adatper part I designed to connect its "Y" to the Super Dust Deputy 4/5.

The Harbor Frieght 2HP Dust Collector comes with a 2-into-1 “Y” joiner to attach to its 5" diameter dust-air inlet. This offers two 4" hose connection points, merged into one 5" for the blower inlet.

Re. is a 5" really OK for merging two 4"? Surprisingly not bad. Here's the math:

4" diameter x 2
Area of a 4" circle = 12.57 in. sq.
Area of two 4" circles = 25.14 in. sq.

Compared to:

5" diameter x 1
Area of a 5" circle = 19.63 in. sq.
So one 5" is almost as big as two 4" … that is, one 5" is 78.12% of two 4".

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Super Dust Deputy 4/5

Super Dust Deputy 4/5 can be bought here (affiliate link): https://amzn.to/3UPkrlx 

The Super Dust Deputy 4/5 can receive either 4" or 5" in from a tool hose, and sends either 4" or 6" out to the dust collector's blower motor. Comes with two adapters (they both can either change the 5" ‘in’ to a 4" ‘in’, or change the 6" ‘out’ to a 4" ‘out’). But I wanted to preserve that 5" in and that 6" out (or at least have the out not smaller than 5" — and for that, see my other part here. For the 5" ‘in’, I modeled up this adapter in SketchUp:

It works a treat to attach the stock “Y” onto the 5" ‘in’ on the Super Dust Deputy 4/5:

In the factory configuration, there is a stock M5 screw that secures the “Y” joiner to the HF dust collector's air inlet. I designed this adapter so it can accept that screw, or some other short M5 screw, in the same way. I also added another hole, so if you like, you can drill out a slightly less than M5 hole in the Super Dust Deputy's inlet, and use a short M5 screw there as well. 

 
As mentioned above, please see my other adapter part designed to go from the 6" ‘out’ of the Super Dust Deputy, into the 5" ‘in’ on the blower motor of the Harbor Freight dust collector. Here's a link: https://www.printables.com/model/1071457-dust-collector-top-adapter-6-to-5-turn-harbor-frei  

For those who are curious on how I configured this setup for 2-stage dust collection, here are the details:

I mocked up my stock, store-bought Harbor Freight 2HP dust collector, so I could plan for rearranging its parts to make my setup 2-stage instead of 1-stage.

In these screen shots below, the plan for the new setup is on the left, and the stock setup is on the right. I set them side by side so the stock setup could be compared with the re-arranged version.

In the stock configuration, the stock hose (marked in salmon color / pink color) is a factory 5" diameter hose. By cutting two portions off, one slightly shorter than 5" in length and another slightly shorter than 6" in length, I will be able to connect the “Super Dust Deputy 4/5” to the blower motor, coming from the 3D printed adapter marked in green (link here), going from 6" down to 5" inlet on the blower / impeller area, and will also be able to connect the stock, factory 5" air outlet on the blower motor, marked in blue, to the 5" air inlet on the separator ring. The white cylinder on top the separator ring represents either the factory bag filter or my pleated canister filter. The empty area under the separator ring would either have the factory plastic bag, or in my case, my trashcan that attaches to a DIY quick-connect MDF ring feature that I had previously modeled and made.

The model currently does not show the casters on the base, but I have the base floating about how high it is on the stock casters.

The basic idea is that I will build a wooden box, attach it to the base, and attach the support rods that hold the separator ring, thus elevating the separator ring to the new higher location. This will also nudge the separator ring closer to the end of the base, allowing room for the new galvanized steel trashcan my “Super Dust Deputy 4/5” is attached to.

Also see (below) my related models used in my conversion from 1-stage to 2-stage on my dust collection:

Dust Collector Top Adapter 6" to 5" - turn Harbor Freight 2HP DC into 2-Stage, using Super Dust Deputy 4/5 - https://www.printables.com/model/1071457-dust-collector-top-adapter-6-to-5-turn-harbor-frei 

Dust Splice Coupler Adapter - from 4" PVC to 4" Dust Hose (based on POWERTEC 70123 O.D. Splice, 4", Black) - https://www.printables.com/model/1077981-dust-splice-coupler-adapter-from-4-pvc-to-4-dust-h 

Dust Splice Coupler Adapter - from 4" Flex Hose to 4" Flex Hose - https://www.printables.com/model/1077997-dust-splice-coupler-adapter-from-4-flex-hose-to-4 

Harbor Freight 2HP Dust Collector outlet port with downward curve (or flip it for upward curve) v1.0 - https://www.printables.com/model/1087419-harbor-freight-2hp-dust-collector-outlet-port-with 

*Amazon links are affiliate links.