Dust Collection - 6" Main Line Into a 4" Intake?

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Forum topic by jjmontague posted 05-24-2012 05:07 PM 1361 views 0 times favorited 6 replies Add to Favorites Watch
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4 posts in 1953 days

05-24-2012 05:07 PM

Hi folks. I’m currently designing a central dust collection system for my one-car garage workshop. I bought the HF 2HP dust collector, which has only a 4” intake (with a 4×4 wye adaptor). I had previously intended to use a 6” main line with 4” branches, but will I see any benefit if it is reduced down to 4” at the DC intake? With that in mind, should I save the money and go with a 4” main line instead?


-- Joe

6 replies so far

View Bill White's profile

Bill White

4408 posts in 3382 days

#1 posted 05-24-2012 05:40 PM

Are you going to move the hose from one machine to an other, or are ya going to fixed piping?
I have the HF DC with aftermarket bags, and just move the 4” hose to the machine in use. My shop is 19 1/2’ X 15’ with the TS in the center.
I do suppliment the DC with a good vac for smaller machines like BS and router table. The lunchbox planer gets hooked to the DC.
I have NO probs with this setup.


View Scot's profile


344 posts in 2818 days

#2 posted 05-24-2012 05:57 PM

I used a 6” main on my old HF system and it worked great.

-- If the old masters had power tools, they would have used them. So get off your damn High Horse.

View crashn's profile


528 posts in 1887 days

#3 posted 05-24-2012 06:30 PM

My HF unit has a 4×4 wye with a 5” inlet to the impeller. Are you sure it is a 4” inlet?

I recently upgraded to a PennState DCSuper35 with 3.5hp 220v motor (free CL find) and boy does that thing suck. I built a thien separator with 6” inlet and outlet, but it has too much power and often implodes the trash can!

-- Crashn - the only thing I make more of than sawdust is mistakes

View crank49's profile


3979 posts in 2393 days

#4 posted 05-24-2012 07:03 PM

My HF 2hp unit also has 2×4” wye into a 5” inlet on the fan.
The goal is balance.
Two 4” pipes is larger in area than one 5”. Will not be balanced.

I have a 4” main line on one side of the wye that I switch between my TS and Jointer.
And a 2 1/2” line on the other side of the wye that I run to my BS or to my belt/disk sander.

The unit works fine with the 4” and the 2 1/2” open and collecting at the same time because the area of a 4” and a 2 1/2” combined are approximately equal to the 5” fan inlet.

A 4” and a 3” into the wye would perfectly balance the 5” fan inlet, but I have no tools with a 3” connection.

Even two 4” pipes would be a better option than a 6”.

You can remove the wye and connect one 5” main to the unit, but 5” pipe is hard (and expensive) to find.

The 6” will work, but the flow will be slower than optimum. Heavy dust might drop out in the pipe.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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4 posts in 1953 days

#5 posted 05-24-2012 08:49 PM

Yes, I do see now that the HF DC has a 5” inlet. So my choices seem to be go with one 5” main line, or save some money and go with one 4” main line. I assume I’d be limited to the major dust collection specialty vendors when buying 5” fittings, right?

-- Joe

View TechRedneck's profile


763 posts in 2279 days

#6 posted 05-24-2012 11:06 PM

I used 4” S&D pipe for my mains and drops to all the larger machines. Spend your money on good metal blast gates that self clean. I also used some good metal tape to seal all the joints. If you glue the joints then when… Not If…you change or add something, just peel off the tape.

For a 2 hp unit just run one machine at a time. Also, get a wireless remote switch now. You will get one anyhow in the long run because with a piped system and blast gates you will actually use your DC every time you use a machine.

-- Mike.... West Virginia. "Man is a tool using animal. Without tools he is nothing, with tools he is all.". T Carlyle

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