Dust Collector - One 6" Intake VS Two 4" Intakes

Hi folks. I'm designing a central dust collection system for my one-car garage shop, using the HF 2HP collector. I'm trying to decide between using one 6" main line with 4" branches, or two 4" main lines with 4" branches. My shop is set up such that all the tools that require dust collection occupy the back half of the room. Picture the tool layout forming a "U" along the perimeter of the side and rear walls. My dust collector is in the bottom left corner of the "U". I figure I can either use two 4" main lines, sending one along each side of the "U". Or I could use one 6" main line and run it up the wall and across the middle of the ceiling, sending branches out to each tool. Using two 4" main lines would make the run easier because I'd only be using the perimeter of the room, but I don't want to make a large sacrifice in dust collection efficiency. Any suggestions would be greatly appreciated!

Joe

Others may disagree, but my general rule is to use main line ducting the size of the DC intake. If yours is 6" with an adaptor to two 4's, I would use a 6" main with appropriate drops. Some drops may be larger than 4". My table saw, for example, takes a 5.

As far as the setup in your shop, keep the runs as short as possible. I am assuming you are using one tool at a time.

Welcome aboard, Joe,

Rick Potter.

If it were me, I'd do the 6" main with 4" drops, unless doing so means making the lengths longer and increasing the # of bends to the critical dusty tools than if left to 4"

I would send a 6" main in both directions. You won't run multiple machines and a 4" main with knock the CFM way down due to the pipe resistance. Avoid as much small diameter pipe as you can. Dave

I already bought the dust collector, but haven't opened the box yet. Looking again at the specs online, it appears it has only a 4" intake with a 4x4 wye adaptor, rather than the more typical 6" intake with 4x4 wye adaptor. This, I suppose, makes using a 6" main line less effective since it will only bottleneck up at the DC intake. With this in mind, would there be any benefit to using a 6" main?

That wye is probably removable. There will likely be a 6" inlet behind it.

Go with a 6" main.

So it turns out the HF DC has a 5" intake behind the 4x4 wye adaptor , so it would be a 5" main line rather than a 6".

It seems 5" duct and fittings are not very common. Do most people using the HF DC use a 4" or a 5" main line?

Quote:

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Originally Posted by Joe Montague

It seems 5" duct and fittings are not very common. Do most people using the HF DC use a 4" or a 5" main line?

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generally you will still be better off with a 6" horizonal and 4 or 5" verticals. The restriction right at the inlet is still better than the restriction of 5" pipe all the way. velocity of the main is your concern but a little slower flow on the horizontal is preferable to reducing velocity at the machine port. Just don't use a 6" vertical. Dave

When I had mine, I replaced the side piece of the DC with a piece of plywood and a 6" inlet. It seemed to work far better and was easier to find 6" parts.

The biggest problem with the HF DC is that it's impeller is too small and it really isn't 2 HP. More like 1.5HP.

The good news is that the price is a steal.

Throw the 2-4 adapter in the trash!

As mentioned, just remove the 5" takeoff from the DC housing and make one that is 6". I used a piece of 1/4" melamine, and a 6" duct takeoff that came from Lowes, I used the adhesive type, and backed up the adhesive with screws. I think I ended up using new bolts to attach it to the DC housing, as I seem to remember the originals being too short using the 1/4" melamine. Just be sure not to use bolts that are too long, they won't hit the impeller, but would likely cause turbulence and impede material flow. A separator is also something you will want to think about. It will removed the chips and the majority of the dust before it gets to filter, there by keeping the filter clean and allowing maximum flow. Also, fine dust smaller than the micron rating of the filter that doesn't reach the filter won't get through it. I built a "top hat" design that sit atop a trash can, and dump it instead of the collection bag. My collection bag barely gets the slightest bit of dust in it.

As Alan stated the impeller is smaller than most, measuring 9.75", but the 12" impeller from a Rikon 60-200 DC is a perfect and easy direct fit replacement. It was $60 + shipping when I got mine.

I ran with the stock Y-branch 4" pipes in 2 directions. My DC is the 1 1/2HP Delta with canister filter on top. The longest run is about 25 feet from the branch feeding the TS. The short side goes straight to the jointer/planer. Blast gates in either direction which can be closed off easily to the branch not in use. I went this way as the Delta is not the most powerful and most info that I have read shows this to be the best arrangement for a unit with limited CFM and not a cyclone.

Joe, I ran two 4" ducts from my 1.5HP Jet (in the interest of time and money) but am planning to upgrade to 6" to get better flow. I would have been better off to have done 6" from the start like you are considering and others are suggesting above. If you can upsize your machine ports, you will realize the full benefit of the 6" duct, otherwise you take a big hit on that restriction.

Adding a pre-separator will help get the heavy dusts out, but it will also cost you on flow at the hood. The separator has a pressure drop associated with it and will therefore reduce the fan volume. You will get less CFM with the separator than you would without it. Since your impellor is small already, I would not opt for the separator to get more CFM at the hoods. A 6" 90 elbow is only about a 1/4" of loss at 750 CFM. If the separator is only 1" of pressure drop (probably more), then it would be like adding (4) 6" 90s to the system. If you have to reduce down to 4" at the separator, then you have even more loss.

Mike