Dust Collection Systems

We were fortunate to obtain a set of new power tools this year, including mitre saw, table saw, drill press and circular saw. We intend to erect a dust curtain to separate the tool area from the rest of the open lab space.

I’m looking for suggestions and recommendations for a dust collection system that will further deal with sawdust and aluminum debris created by these tools.

Thanks.

_Alan

Our schools wood shop has one of those massive ductwork systems.

However the metal shop uses a more simple system of using PVC pipe couplings to change the diameter of a shop vac fitting to the proper size to fit the collection fitting on the band saws, etc.

My family’s personal miter saw has a little 2.5" diameter elbow pipe you put on the back of it and then attach a included bag to, with a pvc coupling (to change the diameter) you could probably hook up a shopvac and use that instead. Then you just have to train your students to be in the habit of turning them on.

Mitre and Table you may be able to have a shopvac attached to permanently, then have another sitting around for the drill press and circular saw.

drill presses usually don’t have any sort of dust collectors (as you really don’t need them), but as for the other 3, you might want to use a centralized shopvac hooked up too all 3 others, and you might want to just vacuum up the metal or wood shavings from the drill press at the end of each day, but you don’t need a dust collector for it.

Yea, that was my thoughts on the drill press, at most you might need to brush the shavings off to the side so your piece sits on the drill press straight but other than that they don’t make a ton of dust.

Dust collection can get serious if you are going to spend a lot of time in the shop. Dust is not just a nuisance, it can also be a health hazard. You can also create a safety hazard by mixing metal and wood ships. (Think about hot metal chips landing in a pile of dry sawdust.) There’s a pretty good book available from Amazon on the subject.
http://www.amazon.com/Woodshop-Dust-Control-Sandor-Nagyszalanczy/dp/156158116X

When I saw the title to this thread I thought you were talking about some of our old robots. Then I realized you were talking about something else.

I have had some experience setting one of these up.

http://www.grizzly.com/products/2HP-Canister-Dust-Collector/G0548Z

The bonus is you can get everything you need from them. All though when my father and I setup this system we used HVAC ducts. Also I reccomend getting the seperator to go with it to reduce wear and tear on the bag and the blower itself.

Chris,
Our dust collection system of that variety is getting so big we don’t have room for any more robots is storage.

Search on “Thien Baffle Separator” and “Pentz Cyclone”. It could make a fun off-season project.

http://billpentz.com/woodworking/cyclone/index.cfm

http://www.cgallery.com/jpthien/cy.htm

http://forum.canadianwoodworking.com/showthread.php?t=33119

I’ve seen teams use shop air to clean drill presses, milling machines, band saws, and bench grinders. This always concerned me as a lung hazard, but I don’t have any authoritative info. Does any have any links they could post ?

**

dust collection really isn’t that big of an issue if you clean up at the end of each day. it only is really necessary for planers, unless you are using a large wood shop. the only tool other than planers that really need collectors are sanders and maybe band saws.

I was speaking more to the wood dust as a health hazard as I don’t typically speak of metal by products as dust. According OSHA… http://www.osha.gov/SLTC/wooddust/index.html

Wood dust becomes a potential health problem when wood particles from processes such as sanding and cutting become airborne. Breathing these particles may cause allergic respiratory symptoms, mucosal and non-allergic respiratory symptoms, and cancer.
Additionally, certain engineered wood products contain additional hazards. An example is MDF and plywood both contain formaldehyde. http://www.flakeboard.com/msds/Flakeboard_Superior_MDF_MSDS.pdf
http://www.timberproducts.com/.docs/pg/400/rid/10010/f/Softwood_Plywood_MSDS_2005.pdf

As far as using shop air to clean metal cutting tools, I have always been told that this created a airborne eye hazard and that a brush and pan were a better practice. In my experience, metal chips don’t hang in the air as readily as wood does. I doubt putting cutting fluid airborne as a mist does ones lungs any favors though. OSHA is a little more vague here… http://www.osha.gov/SLTC/metalworkingfluids/index.html

Your milage will of course vary based upon the amount of time and intensity of exposure. Personally I don’t spend a lot of time worried about it, but if I am going to cut MDF in my garage with the door closed (winter) then I do put on a resperator.

I would hit up your local woodworking store, when my Dad set up his wood working shop he went to Woodworker’s Warehouse and they set him up well. Use dust collection on your mitre, table, and circ saws, bench grinders, abrasive chop saws, etc. You won’t need it on your drill press (tool speed is too low) and I would especially avoid conventional dust collection if you ever use cutting oil on any machines (drill press, mill, lathe, etc).

Wood dust presents an explosion hazard, and metal dust presents a bad electrical hazard (and maybe an explosion hazard as well). In either even it’s not good to inhale solid particles of anything.

http://www.osha.gov/SLTC/wooddust/index.html
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=27413

Edit: kramarczyk beat me to it… freakin’ ninja post.

There is some hazard info on the Bill Pentz site:

http://billpentz.com/woodworking/cyclone/index.cfm#Risks

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.

  1. 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

Thanks to everyone for responding. This is really helpful!

_Alan

Greg, can you elaborate on this a little bit more? At home, I use my shop vac as a dust collector for my band saw and belt sander, moving the hose from tool to tool. I have found that some particles remain in the band saw housing, and the suction at the belt sander is so high that I have lost workpieces into the vacuum box. It’s nothing like my Dad’s shop, where he has a decent ‘particle collector’ (with filter bags in the several dozen micron range) but it’s in a different section of the shop so we’re not breathing it. That system (hard-plumbed, with automatic-switching blast gates) works pretty nicely.

Sure. From a systems standpoint the main difference is that in a dust collector all the particles go through the impeller while in a shop vac the motor/blower is separated by the filter from the debris tank. There are a few reasons these systems are designed differently and it significantly impacts the way the tool should be used.

CFM and in of water - You can easily compare them to speed and torque. CFM is the velocity of the air, and just like in a robotic system the higher the speed the less torque. For dust collection because all of the particles are small with essentially 0 mass they get caught in the airflow and sucked into a dust collector. The smallest Dust collectors are ~ 600CFM while the best industrial “shop vac” I have ever tested was 180CFM (it cost ~$3000). Inches of water is the vacuum pressure or the torque of the system, it does the heavy lifting. Most shop vacs are designed for general cleanup where they will be picking up piles of dust, wood chips, water, etc so the airflow does not need to be high. The highest static pressure I ever tested on a industrial vac was ~90inches of water which was really incredible for a portable unit. Dust collectors are in the 2-3 inches of water. The reason this is important has to do with the tasking of the different machines. If you are focused on sawdust specifically a shop vac will do a good job of picking up the piles after you are done working, but while the machine is generating dust it just does not have the airflow required to redirect the particles into the vac.

The other major difference between the two is safety. The main reason to have a dust collector (beyond keeping a clean shop) is keeping those tiny particles of wood (10microns or less)out of your lungs to avoid things like obstructive pulmonary disease (COPD) and increased risk of cancer. For this dust collectors are WAY better regardless of if you have a HEPA or other really good filter on your shop vac, as it all comes down to filter placement. Since the filter is after the impeller on dust collectors every particle which is in the air caught by the collector hits the filter. The same can be said for the particles in a shop vac in the stream, but unfortunately the motors in shop vacs are also cooled by air, which is sucked in from the side of the unit and expelled again without passing through a filter. This can basically hyper accelerate the sawdust into the air making it a bad situation not just around the machine but anywhere else with open airflow to your workshop.

Additionally it is important to note that the amount of filter material in the system impacts performance over time because people forget to change/clean their filters. I am guessing but I would say that the average shop vac filter has 20times less the filter capacity than a dust collector which means longer running in between filter blinding. While you can get good filters for shop vacs the average one will be much lower in quality and rating (allows larger particles through) than a dust collector filter bag.

Like I said in my earlier post I could go on talking about this topic for quite a while but those are the major differences. As always your mileage may vary based on each situation you are in, but I hope this helps. I am an advocate of using the correct tool for the job and while you can get a 4"inch adapter to connect your table saw to a shop vac you will probably be better with no dust collection and picking up the piles later.

Greg

OK, so the CFM issue is likely the main reason why the shop vac doesn’t do a good job collecting all the dust from the sander, for example. It certainly has the ‘torque’ (vacuum in inches of water) to pull in what it can capture, but the capture range is very small because of the low ‘speed’ (CFM air movement).

Now I get it.

Maybe I can steal my Dad’s system while he’s not looking…:wink:

you could always buy one of these http://www.deltaportercable.com/Products/ProductDetail.aspx?ProductID=24010

it’s the one I designed while still at black & decker.

ow do the 50-786 and 50-760 compare?