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Forum topic by k4zmb posted 08-17-2019 01:31 AM 751 views 0 times favorited 43 replies Add to Favorites Watch
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k4zmb

19 posts in 113 days


08-17-2019 01:31 AM

I have read a lot of Bill Pentz’s Research on that site. But, in depth and very detailed as it is, not being an engineer or physicist, it left me more confused about making a sheet metal cyclone for my 2 hp DC with 4 inch hose connectors. He recommends 20-22 inch top diameter for a 2 hp DC. Given that what is the optimal height of the cone and the optimal inlet, ( from pickup hose) and optimal outlet to DC?
Thanks to any & all who can help with the challenging physics of cyclones.

-- Marc, “When in doubt, err on the side of caution”


43 replies so far

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MJCD

595 posts in 2850 days


#1 posted 08-17-2019 02:18 AM

I can’t directly answer your question… However, I do have a few questions…

A 4” for your main run is far too small (a statement, not a question). A 6” will provide 36/16 = 2.25x the air flow capacity, and can be supported by a 2hp motor… Delta sold a 1.5hp version, with a 6” inlet, for years, and is probably still doing this – I had one for many years.

My recommendation is to get the specs on both Oneida and Clearvue systems, and reverse engineer what you need. That is, both Oneida and Clearvue sell commercial-grade, well-engineered systems (and they charge you for it). Their specs on cyclone inlet diameter, cyclone length and CFM should be available on their websites or on downloadable documentation – though, Clearvue had horrible documentation, the last time I checked. Delta, Grizzly, and the others in this category may provide specs on their equipment, as well.

For example, the Clearvue system has two impeller options – 15” and 16” (last time I looked), so the housing must be approximately 18” in diameter. The cone is probably 3’ long, and tapers to approximately 6”-8”: that is, approximately 18” tapering to 8” over a 3’ length – again, this information should be ascertainable from close review of their website/documentation information.

A final recommendation is a 6” main run, with 4” drops to the machines; or if possible, replace the machine connections with 6” orifices; otherwise, the 4” runs will choke the CFM throughput.

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therealSteveN

3606 posts in 1053 days


#2 posted 08-17-2019 02:22 AM

Not an eggspurt on cyclones, but I have seen a bunch of them, and seen even more comparisons about many of the ones available. They come in a variety of shapes, sizes, inlet sizes, and outlet sizes. I don’t have a quibble with you trying to make one up, but I would make it look perzactly like the appropriate sized Onieda Dust Deputy. They generally kick butt in comparison testings. Also of all the cyclones, and make it at home designs, I don’t hear about people having to empty them, before being filled, because they almost lost all suction.

On the HF’s I see most often people saying to knock off the 4” splitter cap, and keep it 5” till you get really close to the machine. As above 6” is also a possibility, but would require some work on the HF motor, it comes out as 5”

-- Think safe, be safe

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MJCD

595 posts in 2850 days


#3 posted 08-17-2019 02:37 AM

The Super Dust Deputy is an excellent solution. I had one for many years, and it is still in-use – I added a mobile base, and sold it to upgrade to my large Clearvue.

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k4zmb

19 posts in 113 days


#4 posted 08-17-2019 11:21 AM

Thanks to all of you for your feedback, input and advice. I have contacted Oneida and received specs and dimensions of their 4” Dust Deputy, ( they recommended the 4” for my HF DC). I have scrapped my original plan based on Pentz’s figures and will have local machine shop cut and roll a piece of 22 g sheet metal that I have to Oneidas specs. I’ll rivet then seal the 1” seam. The top will be 3/4” plywood with 4” outlet to DC, (Oneidas’ recommendation), with a very short, less than 18” to DC inlet. As HF uses 4” hose for collection, I’ll keep 4” cone inlet. Considering using 5” or 6” hose to DC. Or should I convert 4” to 6” to cyclone inlet?
I spent two + hours sealing all openings on my older Rockwell TS, which greatly improved dust pick up. I’ll upgrade when finances allow to a larger impeller and a Wynn filter. I’ll post pics when I have something worth showing. Thanks again to all.

-- Marc, “When in doubt, err on the side of caution”

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k4zmb

19 posts in 113 days


#5 posted 08-17-2019 11:34 AM



I can t directly answer your question… However, I do have a few questions…

A 4” for your main run is far too small (a statement, not a question). A 6” will provide 36/16 = 2.25x the air flow capacity, and can be supported by a 2hp motor… Delta sold a 1.5hp version, with a 6” inlet, for years, and is probably still doing this – I had one for many years.

My recommendation is to get the specs on both Oneida and Clearvue systems, and reverse engineer what you need. That is, both Oneida and Clearvue sell commercial-grade, well-engineered systems (and they charge you for it). Their specs on cyclone inlet diameter, cyclone length and CFM should be available on their websites or on downloadable documentation – though, Clearvue had horrible documentation, the last time I checked. Delta, Grizzly, and the others in this category may provide specs on their equipment, as well.

For example, the Clearvue system has two impeller options – 15” and 16” (last time I looked), so the housing must be approximately 18” in diameter. The cone is probably 3 long, and tapers to approximately 6”-8”: that is, approximately 18” tapering to 8” over a 3 length – again, this information should be ascertainable from close review of their website/documentation information.

A final recommendation is a 6” main run, with 4” drops to the machines; or if possible, replace the machine connections with 6” orifices; otherwise, the 4” runs will choke the CFM throughput.

- MJCD


Steve, i did get specs from Oneida. I told them that I had 2 hp DC with 4” inlet & they recommended the 4” cyclone.should I remove the 4”Y and use a 5” to 6” reducer, if I can find one, into the impeller housing? Would that improve CFM, but reduce air speed? I take your advice that Oneida has got this figured out, because my small Dust Deputy does a great job with just the shop vac.
I’m just trying to figure out the connections between DD & DC. I plan to keep that connection short & on a mobile stand to get close to each machine to improve collection and decrease air flow resistance. Given that do you suggest using 6” pvc or duct to machine & then reducer to 4” machine port?
Thanks, Marc

-- Marc, “When in doubt, err on the side of caution”

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ibewjon

902 posts in 3272 days


#6 posted 08-17-2019 02:23 PM

With a 1 1/2 HP, I think the 6” duct is oversized. Wood magazine articles have recommended 5” steel duct, with 4” being too small, except for drops. That is how I built my system, and no complaints. I am going to purchase an industrial style air speed / CFM meter soon just to get some real numbers for my system.

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k4zmb

19 posts in 113 days


#7 posted 08-17-2019 02:43 PM

With a 1 1/2 HP, I think the 6” duct is oversized. Wood magazine articles have recommended 5” steel duct, with 4” being too small, except for drops. That is how I built my system, and no complaints. I am going to purchase an industrial style air speed / CFM meter soon just to get some real numbers for my system.

My DC is a 2 hp, does that give me much advantage over the 1 1/2?
I could not find any 5” metal duct in local big box stores, so that presents a challenge. I suppose I could make my own from 6” by cutting, riveting & soldering.
BTW, I purchased a Proster anemometer that does have CFM mode. It seems to work well.
Thanks for the offer input.
Apparently there is some margin on specs as there are a lot of people using various sizes of cyclones, duct sizes, etc. Do you have an opinion on the Jet 12” impeller to replace the stock HF one?

-- Marc, “When in doubt, err on the side of caution”

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ibewjon

902 posts in 3272 days


#8 posted 08-17-2019 04:04 PM

I believe both Menards and Home Depot and probably Lowe’s can get the 5”, 26 guage, just not a shelf item. And others have found it to be cheaper than PVC. I bought mine from a heating supply company. I do not have a cyclone, no real estate to park it in. My collector is a 2 HP from north state machinery about 25 years ago. It draws 9.4 amps on 250 volts. I replaced the bags with the Jet pleated filter and added a vortex cone. Check your amps while running if you can. Motor tags from overseas are inaccurate these days. Mine is a stock impeller, unknown diameter. I have read that an anemeter does not really work for this, so I will be ordering from Dwyer. About $150. I have connected their instruments many times, and they are a long established company. Look up dust collector ductwork on Wood magazine.

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Fred Hargis

5683 posts in 2972 days


#9 posted 08-17-2019 05:51 PM


My DC is a 2 hp, does that give me much advantage over the 1 1/2?

- k4zmb

You said earlier it was the HF DC you have. That is almost certainly not a true 2 HP, more likely 1.5. It’s a good bet that a 12” impeller would overload that motor (besides, it may not fit in the blower housing) but there was a thread here some time back where someone used an 11” (I think) Rikon impeller and seemed to be relatively satisfied with it. I searched a little and couldn’t find the thread, but maybe whoever it was will see this and chime in.

-- Our village hasn't lost it's idiot, he was elected to congress.

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k4zmb

19 posts in 113 days


#10 posted 08-17-2019 08:11 PM

Thanks. I might have seen the impeller upgrade on YT, and it could have been an 11 inch impeller. Is there an accurate way to measure hp other than extrapolating from the amp reading with a meter?

-- Marc, “When in doubt, err on the side of caution”

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Fred Hargis

5683 posts in 2972 days


#11 posted 08-17-2019 09:07 PM

None (that I’m aware of) that we mere mortals would be able to do.

-- Our village hasn't lost it's idiot, he was elected to congress.

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ibewjon

902 posts in 3272 days


#12 posted 08-17-2019 09:22 PM

Amps. X. Volts. =. Watts. Watts ÷ 746 equal approximate HP. That is the mortal way.

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Todd_R

18 posts in 226 days


#13 posted 08-17-2019 11:09 PM

http://www.clearvuecyclones.com/forum/forum/clearvue-cyclones/product-questions/477-what-size-cyclone
Note in his sizing comments a 1.64 ratio for the cone (with a 18” diameter).

However, contacting Oneida to get specs isn’t a bad way to go. Their systems definately work as I can attests since I have a couple of their cyclones now.

That said with your design (using the 4” port with a HF 2 HP motor) I would keep the run very short and direct to your system so as to obtain the performance necessary. If you don’t you could end up with a lot of dust sitting in the ducting and a potential fire risk.

-- Todd

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HackFabrication

155 posts in 191 days


#14 posted 08-18-2019 12:38 PM


It s a good bet that a 12” impeller would overload that motor (besides, it may not fit in the blower housing) but there was a thread here some time back where someone used an 11” (I think) Rikon impeller and seemed to be relatively satisfied with it. I searched a little and couldn t find the thread, but maybe whoever it was will see this and chime in.

- Fred Hargis

My on-going HFDC build (many have done this using the Rikon 11 7/8” impeller: Dust Collector

-- "In the end, it's all Hack..."

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EarlS

3030 posts in 2827 days


#15 posted 08-18-2019 03:05 PM

For what you will likely spend having the sheet metal rolled, your time, etc. IMO you would be money, time, and confusion ahead to simply by the metal version of the Oneida 5” or 6” Super dust Deputy.

As for sizing, a 6” main will allow you to use all of the cfm the blower provides and minimize pressure loss in the duct work. Reduce to 5” on your drops to the equipment and then reduce to the dust port size on the equipment (4” usually).

I just bought a Delta 50-850 (1.5 HP, 1200 cfm, 11” WC) that I intend to retrofit with a filter cartridge, 6” SDD, and 6” mains. I also found a YouTube video where the guy also took a bunch of cfm readings along the way. Being an engineer, I’m going to get an anemometer and maybe a manometer and do the same thing he did and document the performance.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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