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Forum topic by AbranV posted 12-12-2011 07:32 AM 3854 views 0 times favorited 17 replies Add to Favorites Watch
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30 posts in 2483 days

12-12-2011 07:32 AM

My friends, I have a quick question for you all. I have too small of a shop for a standard dust collection system, so a shop vac is my best option. My current vac can’t keep up with my needs, and I’ve been shopping around for a while.

My question for everyone is what is the most important factor for a shopvac?

Would a higher hp or more CFM be better for woodworking?

For example, would a 3.5hp vac with a 300CFM rating be better than a 6.0hp vac with a 175cfm rating, or the other way around?

Thanks All!

-- I'd rather be making sawdust.....

17 replies so far

View derosa's profile


1577 posts in 2831 days

#1 posted 12-12-2011 07:44 AM

I have a 6hp ridgid that is supposed to have about 167cfm and while it isn’t the best solution it does a really good job of keeping down the dust levels in the shop. I would assume that hp and cfm would be directly related and be a little dubious of the higher cfm rating of a lower powered vac. Admittedly the smaller and weaker ridgid I bought for 25.00 seems to collect nearly as much dust but the noise on it is incredible and requires ear protection for any extended us where the larger 6hp is really quiet in comparison and won’t wake the baby while cleaning the house. I found the hepa filter for it does a really good job of preventing the dust from getting into the motor and from being blown out the back. However a bag is needed to cover it to keep the pleats from filling quickly with the larger dust particles.

-- --Rev. Russ in NY-- A posse ad esse

View fussy's profile


980 posts in 3046 days

#2 posted 12-12-2011 08:35 AM

If you get a shop vac, get one on sale at one of the big box stores (My daughter picked up a shop vac smal-mart for me for $20). I paid $40 Slowe’s year4s ago for a ‘6hp’ 16 gal. They do a good job on single tools like sanders, routers,etc. ONE TOOL AT A TIME with a shop vac or small dc.

I built a Thein Separarator ( and built a roll-around cart for it with it in a 35 gallon drum and the vac on top. Works great, nothing much gets past it to the filter, but use a HEPA filter (not hepa-TYPE; not the same thing) anyway. Same footprint as the vac, just taller with more capacity, and no cleaning the filter or trying to dump that clumsily shaped vac. HP in a vac is rediculously overstated as is cfm. All about the same. It’s how you use them.

Go to Phil Thein’s site that I listed above. Go to the oldest pages aND read forward. There’s more info in 10 pagers there than you’ll find anywhere else.


-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

View NiteWalker's profile


2737 posts in 2572 days

#3 posted 12-12-2011 11:33 AM

I gauge by amps.
My shop vac I bought from lowe’s several years ago; it’s “5.5 HP” and 12 amps. No complaints.
Just pay attention to the amp rating and container size; those are the two most important specs IMHO.

-- He who dies with the most tools... dies with the emptiest wallet.

View crank49's profile


4030 posts in 2966 days

#4 posted 12-12-2011 01:04 PM

Th HP ratings vacuum cleaner motors are all lies.
They are not all based on the same parameters.
The numbers have no value to anyone but the manufacturer as a sales tool.

CFM ratings alone are no better.
The CFM rating combined with the static pressure would be useful but they rarely give you both because then they can’t cheat and distort the value for sales promotion.

Realistic numbers on a vacuum would be around 120 CFM at 90” H2O static with a 1 1/2” opening.
That same vacuum might do 175 CFM at 60” H2O static with a 2” hose.

It’s not perfect, but the only number you are likely to get that is comparable between different machines is the amps like NiteWalker said; or Watts, which you divide by volts to come up with amps..

View ryansworkshop's profile


35 posts in 2363 days

#5 posted 12-12-2011 02:46 PM

In my small shop I do it this way.

I sweep up, then dust pan or coal shovel to a 32 gallon trash can.

Then I invent hose to blow and blow remaining dust out the garage door.

If needed I vac up the little that is left.

In a shop vac, I don’t want a large one to take up room or to be to heavy to lift when full. Mine is 6 gallons, 3hp and fine.

Total shop clean up time, under 10 minutes.

-- A small shop has it's pro's and con's. Never big enough, but easy to clean.

View Chipy's profile


374 posts in 2589 days

#6 posted 12-12-2011 03:01 PM

Get a Dust Deputy cyclone separator!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Oneida IND.

View Craftsman on the lake's profile

Craftsman on the lake

2790 posts in 3433 days

#7 posted 12-12-2011 03:06 PM

These are great ideas. Another one is to get a tall one. I’ve had two craftsman vacs. The older one was very tall. The other, like todays models, short and squat. The taller one held more sawdust simply because the bag inside was higher and didn’t get clogged like the shorter one. Once the bag is in the sawdust suction is limited, you have to constantly empty it when it’s 1/4-1/2 full. Like some said, a cyclone or thein would help this.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View RogerM's profile


792 posts in 2395 days

#8 posted 12-12-2011 05:15 PM

Ditto on the Dust Deputy. Only way to go.

-- Roger M, Aiken, SC

View richgreer's profile


4541 posts in 3070 days

#9 posted 12-12-2011 05:47 PM

For me, a big issue with shop vacs is their noise level. Relative to dust collectors, shop vacs have been, traditionally, very noisy.

I see that some of the newer models are being designed to run quieter.

For some (perhaps many) this is not a big deal. I just know that if I were buying a shop vac one of the criteria I would be considering is noise level.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View NBeener's profile


4816 posts in 3169 days

#10 posted 12-12-2011 06:26 PM

Aside from a HEPA filter, I literally did encase my filter in an old pair of panty hose (I find them too itchy, these days).

Does a GREAT job of keeping the filter from clogging.

-- -- Neil

View dbhost's profile


5710 posts in 3227 days

#11 posted 12-12-2011 07:03 PM

No shop vac is going to be able to move enough air to be a true dust collector. Many low end dust collectors don’t either…

IF you can find a way to fit one in to your shop, I strongly reccommend a true dust collector with a 1 micron filter, and a separator. The Thien baffle has been mentioned. They can be installed IN the DC itself to save space…

The Harbor Freight / Central Machinery 2HP DC is a great bargain. You have a Harbor Freight store on Portland Road in Salem… (I grew up in Corvallis… kind of know the area…).

Before you say you can’t fit it. Remmeber, there are plenty of guys running these in shops based on 10×12 sheds… Get creative with storage and I bet you can fit it…

-- Please like and subscribe to my YouTube Channel

View crank49's profile


4030 posts in 2966 days

#12 posted 12-12-2011 08:32 PM

I have both.
A shop vac, a 1hp portable DC and a 2hp HF DC.
Wait, that’s three.
Well, I haven’t used the 1hp DC yet; it’s going in a routher table I haven’t built yet, so it doesn’t count.

Honestly, the Shop vac takes up almost as much room as the 2hp DC.
Some people put the DC unit outside and just run the duct out to it. No room. No noise, No dust.
That arrangement will cost you some heating/air conditioning expense, however.

View Bill White's profile

Bill White

4929 posts in 3956 days

#13 posted 12-12-2011 09:14 PM

Ridgid has a muffler for the vacs. I have one on mine, and it makes a big diff. Fits in the exhaust port.
The one I have has the detachable motor that will double as a blower.
I also have the HF DC with felted bags top and bottom. Got the bags from Highland Woodworking. They (the bags) a a great addition to the DC.


View live4ever's profile


983 posts in 3006 days

#14 posted 12-12-2011 10:06 PM

Once you add up all the costs of a shopvac-based DC system, you’ll find it’s not any cheaper to go that route (possibly more expensive). So if there’s any way you CAN use a real dust collector, such as the Harbor Freight 2hp DC, definitely go that way. The remainder of my post is based on the assumption that it’s not practical for you to do so, whether that’s for space or noise.

I use my Fein Turbo I for most of my dust collection needs. As others have said, a shopvac doesn’t provide TRUE or FULL dust collection, but it can get most of the debris and dust depending on the tool. It’s a decent compromise for those of us that just can’t have a real dust collection system, whether it’s because of space, noise, electrical constraints, whatever.

I use the Fein to collect from my cabinet saw, bandsaw, planer, router table, drum sander, spindle sander, as well as handheld power tools. The one tool that it falls hopelessly short at is the bandsaw. For the rest, it does a decent job.

Noise [disturbing the neighbors] was the overriding concern for me which is why I shelled out the cash for the Fein. You will thank yourself for getting a quieter model – some of the larger models are 95+ db, which is annoying for long periods of time even with hearing protection. Note that you don’t have to spend Fein money for a quieter vac – there are several reasonably-priced models now that have their noise levels below 80db.

Also, you will need to upgrade the OEM filter to AT LEAST a 1 micron, if not HEPA, filter. And lastly, do yourself and your vac a huge favor by adding a separator, either the Dust Deputy or Rockler’s Dust Right Vortex. These ensure that only the finest particles are reaching your vac/filter, and all the big stuff is being deposited in the separator’s bucket for easy cleanup. These unfortunately do enlarge the footprint of your shopvac setup, so it can be argued that you’re reaching dust collector size. However, they’re separable and can be independently stored/moved, so it’s not the same thing. Trust me – I have a really cramped shop with lots of obstacles. The shopvac and separator can get around easily, while the 2hp DC absolutely cannot, which is why it sits in the corner unused.

-- Optimists are usually disappointed. Pessimists are either right or pleasantly surprised. I tend to be a disappointed pessimist.

View gfadvm's profile


14940 posts in 2686 days

#15 posted 12-13-2011 04:27 AM

Bill White, I bought one of those ‘mufflers’ for my 6 horse Ridgid and couldn’t tell ANY difference in sound level so I took it back. Just my 2 cents.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

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