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

[Steve Kohn]

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.

I did something similiar on my Grizzly, except I bought a 6" inlet from one of the big box stores and used a metal cutting blade on my saber saw to cut the opening larger. Used foam tape and sheet metal screws to attach the inlet to the plate and then remounted the plate on the DC. I then made sure the impeller didn't hit anything and then powered it up. All my main ductwork now starts at 6 inches and gets reduced from there.

[Jim Neeley]

One 6" duct will have lower pressure drop per foot of duct than two 4" ducts. The small part is because the 6" has more cross-sectional area than the two 4" ducts combined but mainly because there's less pipe surface area to develop the friction. Make the Y as close to the tool as is feasible.

Just my opinion.. YMMV.

Jim

[Alan Lightstone]

Here's a picture of mine (boy, had to dig to find the picture of it):
HF DC 6in outlet modification.jpg

[Joe Montague]

Great ideas, guys! I think I'm going to enlarge the hole on my DC to accomodate a 6" inlet. Does anyone know of a larger impeller that is a drop-in replacement for the stock impeller?

[Kevin W Johnson]

Great ideas, guys! I think I'm going to enlarge the hole on my DC to accomodate a 6" inlet. Does anyone know of a larger impeller that is a drop-in replacement for the stock impeller?

I guess you missed my ealier post......

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.

[David Kumm]

Great ideas, guys! I think I'm going to enlarge the hole on my DC to accomodate a 6" inlet. Does anyone know of a larger impeller that is a drop-in replacement for the stock impeller?

Joe, I'm not discouraging you from enlarging the inlet because I believe you will receive some benefit but enlarging an inlet or or replacing a fan within an existing housing will not automatically improve your life. There are relationships at play that require lots more knowledge than I posess to ensure increased cfm or efficiency. A fan will be designed for a maximum intake size based on the blade configuration and while a smaller inlet just reduces the cfm a larger opening may reduce efficiency so the cfm delivered comes at a greater relative amp draw if at all. The same thing occurs when changing fan diameter within a housing. The limitation will be the size of the housing plate which is usually not much bigger than the stock fan. Dave

[Kevin W Johnson]

Joe, I'm not discouraging you from enlarging the inlet because I believe you will receive some benefit but enlarging an inlet or or replacing a fan within an existing housing will not automatically improve your life. There are relationships at play that require lots more knowledge than I posess to ensure increased cfm or efficiency. A fan will be designed for a maximum intake size based on the blade configuration and while a smaller inlet just reduces the cfm a larger opening may reduce efficiency so the cfm delivered comes at a greater relative amp draw if at all. The same thing occurs when changing fan diameter within a housing. The limitation will be the size of the housing plate which is usually not much bigger than the stock fan. Dave

Ah, but the only difference between the HF DC and the Rikon 60-200 is the size of the impeller. I've studied the Rikon at Woodcraft, and I have the HF unit personally. For whatever reason, Harbor Freight chooses to use a smaller impeller, heck I guess it saves them $2 in material cost. Otherwise they are the same unit, and the impellers swap perfectly between the two.

I've personally put the Rikon impeller in mine as well. Running amp draw with the 12" Rikon impeller is 13 amps, which might be tenths of an amp different from the stock impeller at most. I checked it before and after, and the difference, if any wasn't note worthy.

[David Kumm]

Kevin, I agree with you and Joe. Just not wanting others to think they can swap pieces and automatically get a better result. 12" impellers are kind of the norm for a 2 hp motor. I think Oneida may even use a larger one but theirs is BI which limits the amp draw compared to a straight blade. I'm assuming yours is a straight radial? Dave

[Alan Lightstone]

I tried getting a straight answer from Grizzly as to whether their impellers would work. I think it will, but they never would answer the question.

The drop in Rikon sounds promising along with the 6" inlet from Lowes.

[Michael W. Clark]

Running amp draw with the 12" Rikon impeller is 13 amps, which might be tenths of an amp different from the stock impeller at most. I checked it before and after, and the difference, if any wasn't note worthy.

Kevin,
If you are pulling more air with a larger impellor, why didn't the amp draw increase? Or do I misunderstand your post?

The HP (amp draw) varies greatly with CFM change. Granted, you may have a more efficient impellor if they are different design, other there should be a significant increase in HP.

Mike

[Ole Anderson]

There is a lot more to impeller performance than just the diameter. Width, angle, curvature and number of blades all affect the performance curve.

[Alan Lightstone]

Kevin,
If you are pulling more air with a larger impellor, why didn't the amp draw increase? Or do I misunderstand your post?

The HP (amp draw) varies greatly with CFM change. Granted, you may have a more efficient impellor if they are different design, other there should be a significant increase in HP.

Mike

I would have thought that the amp draw would increase also.

[Joe Montague]

I guess you missed my ealier post......

Kevin, actually I DID read it. The funny part is, I thought I had read it somewhere else, and couldn't remember where I had seen it! I should've reread my own thread first! Thanks for that!

[Joe Montague]

Kevin, did you buy the Rikon 12" impeller directly from Rikon?

[Kevin W Johnson]

Kevin,
If you are pulling more air with a larger impellor, why didn't the amp draw increase? Or do I misunderstand your post?

The HP (amp draw) varies greatly with CFM change. Granted, you may have a more efficient impellor if they are different design, other there should be a significant increase in HP.

Mike

Case of bad memory, and making too many changes to my DC system and not writing down any of my measurements.

So, to solve that I swapped the original impeller back in and took some measurements as measured by a Fluke 337.

On the original HF impeller, inrush = 68.5A running = 10.5A

On the Rikon impeller, inrush = 70.1A running = 12.2A

Kevin, did you buy the Rikon 12" impeller directly from Rikon?

Yep, Just call Rikon 877-884-5167 7:30am-4:00pm ET, and ask for parts, and you need the impeller for a 60-200 dust collector.