[Greg Needel]

This is one of those topics I could write quite a bit on, as I designed woodworking dust collection systems for Black & Decker (delta machinery). Basically there are 3 main factors (and a bunch of smaller ones) that determine how effectively a system will work.

1) Air volume over time (typically called CFM even though that is just units). This is how much volume of air the machine can move. While in most cases more is better there are some exceptions and a whole lot of phewy out there hidden by marketing.


2)static pressure (inches of water) - this is basically how much force the vacuum can lift. Google it for more info.

3) Filtration - The particle size that the output filter will let through during opperation.


A shop vac is not a dust collector, actually they are not even in the same ball park, as a typically home depot unit will give you ~60CFM and 10-15 inches of water. While a good woodworking dust collector is at least 1200 CFM and 1-2 inches of water. The major difference being that the debris in a dust collector flows through the impeller, while in a shop vac it does not these differences are important to understand as one should not be substituted for the other.


When selecting a dust collector you need to decide early if you want a mobile unit which you move to each machine as needed or a semi-permanent one which the dust collector is stationary and you run hard piping to each machine. As with all decisions in life there are advantages and disadvantages to each. A few factors which you should think about are how the space is going to be used. Is the shop going to be arranged in the way it is now for a long time? Are you willing to invest in a larger capacity dust collector for a fixed plumed unit? (which you will need for losses due to the pipe/hoses) Do the people using the shop have the discipline to move/attach a mobile unit to every machine before it gets used? etc

The major things you need to figure out is how your space will be used and that will decide alot of this for you. Know that not all tools are created equal, as my 5HP table saw requires a larger dust collection system than my chop saw. The longer you run the hose from the dust collection unit to the tool the higher the drop off in CFM you will see. When you read that a dust collector is 1200 or 1500 CFM that is rated at the tool with no hose connected to it; add 10 ft of hose to the unit and you will likely be ~50% of the maximum. The output filter is probably the most important part of the whole system. Many companies will sell a unit cheap because it has a bad filter on it. Dust collectors will spec the "micron size rating" of their filters the lower the number the better because it will catch the smallest particles which are also the ones that pose significant health risks. The down side of things is that the higher filtration you get the more likely your filter will get clogged and the performance of the whole unit will suffer. I would recommend a 1-3micron canister filter because they are easy to clean and provide sufficient filtration.

In my home wood shop I use a mobile unit (delta 50-760) which I can connect to each machine before I use it, I do this because I know the performance will be better than if I plumb my shop. Also I have a 1micron canister filter on it.




A couple of side notes: Cyclones as mentioned above with the bill pentz website are good, but a cyclone is just a separator. Basically what it does is allows particles to drop out of the airflow before reaching the filter, providing a longer time in between when you need to clean your filters. Because of this if you have a cyclone it will typically be a lower initial CFM but more consistent over the use of the machine.

As for brands, I worked on units made under the brand "delta machinery" one thing I can share is that many of the units come out of the same factories in Asia, with minor and major differences and you should do your research online before buying as not all machines are created equally even under the same brands. There are plenty of web forums that specifically discuss each unit.

Any further questions don't hesitate to ask.

Greg