Dust collection

[Tim Marks]

...but why waste my breath. Not many listen anyway.

Cheer up, Chuck. Winter will be over in about 6 months in the Dakotas...

Seriously, one of the best things you can do to improve your enjoyment of the hobby is spend a little time improving dust collection. Not just because the health nazis say you have to or you and your family will die a horrid death, but because it is just no fun having to clean up messes. And nothing can make a huge mess faster then power tools.

Chuck has a good suggestion; an hour or so tinkering with the way your contractor TS collects dust can save you alot of time. Plus, it is more fun to make something (ie. table saw templates to block air flow) then to repeatedly sweep up (and breathe) dust over and over. Add a baffle plate to the back with cutouts for the motor belt which sticks to the back of the saw with magnets (be careful, a couple of members here bolted the baffle plate in place, and then broke their TS trunnions when they tilted the blade without removing the baffle plate). Add a baffle plate to the bottom with a 4" hose connection to connect your DC to. If you are really ambitious, replacing the bladeguard with one that collects dust will help too.

Go for a 2HP canister type DC; they move alot more air and are alot better for your health. The Grizzly G0548 runs $499 delivered; I think it would be worth it to stretch your budget a bit to get a full 2 HP and a filter.

You could also just buy a 2HP version with a bag that is in your price range (G1029Z is $334 delivered) and spend $150 later to get a filter. The downside of this is that the G0548 is a much better machine, and the solid rectangular plenum between the motor and the bag ring adds a lot of stiffness, and will improve airflow and separation efficiently quite a bit.

You NEED 2 Hp. Honest. And it is not just a Tim Allen thing.

[Eric Haycraft]

Sure was. I haven't tried your design, but it looks like it can break the 400cfm barrier.

[glenn bradley]

Anything over like 400CFM will clean out that trash can cyclone, so it is almost useless on most DC setups. Someone on here posted a modified lid that you build yourself for around 20 bucks that should get by the 400CFM problem, so I would do that first. Just search the forum and I am sure you can find it.

I run a 650 CFM with a separator and it works great. I only have to change the "fines" bag about once for every 6-or-so trashcan emptyings. My lid is the Woodcraft style which puts a bit more of a hit on the CFM than the Griz / Rockler style.

Maybe the internal elbow is slowing the debris more and this is what makes mine work so well. That is, it works well, at least in separating, I'd like more CFM back but you can't have your cake and eat it too.

[Joe Jansen]

Thanks for the information.

After research i think I am going to pick up the delta 50-760.

I appreciate the help

Joe

[Dave MacArthur]

I could give you a few pointers on how to make your contractors saw more efficient at dust collection, but why waste my breath. Not many listen anyway.

LOL... not THAT sounds like someone losing spirit! Cheer up Chuck! IMO, one of the best threads I've ever read at SMC is your thread on modifying your contractor's saw for dust collection, all the clever metalwork, etc.! I think that there are actually multitudes for folks out there with a contractor saw who are totally content with it (as I was for 10 years!), who love your ideas. Over my entire time spent with WW tools, I ABSOLUTELY have spent more time thinking about my contractor's saw, dust collection, the back opening, cabinet under, etc... than anything else. And I ENJOYED doing so! I only wish I had run across SMC and your wonderful posts and thoughts many years ago. Keep up the spirit, you do a good service to the most important segment of our hobby: the next generation, beginners, etc..., as well as the vast majority of us who don't have unlimited budgets.

Joe, check out Chuck's thread on controlling dust from your table saw-- Bill Pentz says, and I agree, that the very first step in dust collection is to control it at the source with good hoods/pickup, and Chuck's design is top notch.

[Chuck Lenz]

WOW Dave, I'm practically speachless. Thankyou very much, I REALLY apreciate it and feel honored.

[Quesne Ouaques]

Hi Joe:

I have had the Delta 50-760 for a while now, and I could not be happier with it. For it's size and HP rating it sucks big time!

There is only one thing I would add that may have not already been said. If you are planning to use it as a centralized collector, and you have any runs that are greater than 12 ft, I would advise setting up your main branches with 6" duct. Overall, you will lose less suction to static pressure and the velocity in the mains will be more than adequate to keep the heavy stuff moving.

After reading Sandor Nagyszalanczy's excellent book, I decided to run some simulation tests with my 50-760 (before I bought all of the ductwork, of course) using both a 4" and 6" main. The difference was dramatic with the 6" performing much better. My drops coming off the mains are all 4" which makes for a very straightforward design.

There is some more detailed information in an old thread I started a while ago.

http://www.sawmillcreek.org/showthread.php?t=63798

Good luck!

[Howard Acheson]

Let me recommend you pick up the current Wood Magazine. They have a review of small dust collectors. In addition, they have lots of good info about setup and filter bags. Most of those tested "leaked" fine dust particles into the shop.

[Prashun Patel]

I read the article in Wood too.
The Delta 50-760 and the Grizzly 2hp (can't remember model#) were recommended.

[Chuck Lenz]

You could also just buy a 2HP version with a bag that is in your price range (G1029Z is $334 delivered) and spend $150 later to get a filter. The downside of this is that the G0548 is a much better machine, and the solid rectangular plenum between the motor and the bag ring adds a lot of stiffness, and will improve airflow and separation efficiently quite a bit.

You NEED 2 Hp. Honest. And it is not just a Tim Allen thing.

I'm running the 2 HP Grizzly G1029Z. I looked into buying the solid rectangular plenum and bag mount and adding it to the G1029Z, but I'm not sure if it will fit because the impeller houseing on the G0548 is a different part number. But the top of the G1029Z impeller houseing looks like it would fit. I'd much rather have that then the 5" hose for the reasons that Tim described. I put a set of new low micron Powermatic bags on it that a friend of mine gave me that switched to a pleated canister filter right away when he bought his DC. Overall though I'm pleased with the unit. I'm also running a Delta 50-875 air filtration system and use a AOSafety 95190 Woodworker's Reusable Respirator.

[Dave Dye]

l have a 18X40 shop. I bought the Grizzley G1028Z and I love it. I have it hooked to my jointer/planer and my table saw. I use blast gates and only use it for those machines for now. I bought it because I don't really have room for another 220 machine right now. This machine can be used with 110 or 220. Work wonderful.

[Chris Stolicky]

Hi Joe:

I have had the Delta 50-760 for a while now, and I could not be happier with it. For it's size and HP rating it sucks big time!

There is only one thing I would add that may have not already been said. If you are planning to use it as a centralized collector, and you have any runs that are greater than 12 ft, I would advise setting up your main branches with 6" duct. Overall, you will lose less suction to static pressure and the velocity in the mains will be more than adequate to keep the heavy stuff moving.

After reading Sandor Nagyszalanczy's excellent book, I decided to run some simulation tests with my 50-760 (before I bought all of the ductwork, of course) using both a 4" and 6" main. The difference was dramatic with the 6" performing much better. My drops coming off the mains are all 4" which makes for a very straightforward design.

There is some more detailed information in an old thread I started a while ago.

http://www.sawmillcreek.org/showthread.php?t=63798

Good luck!

Congrats on the purchase. I have one on the way as I write this...

I have spent a lot of time reading a vast number discussions on DCs. I have a question that I would like to get some insight on:

Since the 50-760 has a 5" intake, what is the advantage (versus disadvantage) of using 5" duct over 6" duct? I plan on using metal ducting. Wouldn't you lose static pressure and flow if you move up to 6" (~28.25 sq-in) from 5" (~19.6 sq-in)? I will also be adding a cyclone-collection can. I currently have the woodcraft one, but may end up building one down the road (another topic someday - using 5" inlet/outlet for the lid rather than 4").

My shop is roughly 12' x 16' and I am contemplating putting it right outside of the actual shop space. The part that is actually considered my 'shed'. I only anticipate using one machine at a time with it. The way the shop is set up right now my lathe would be the furthest away from the actual DC; probably 18' or so including vertical runs of pipe. I have the basic bench power tools except a planer (so far).

Thanks ahead of time....

[David Parker]

Hi Chris,

I'm planning on buying the Delta 50-760 also with an arrangement similar to yours. Here is my limited understanding of dust collecting and duct size (which may be wrong, please correct me if I am):

The goal in dust collecting is to move as much air as possible at the site of dust pickup. I remember reading one post that said it takes 800 CFM or more at the intake site to adequately clear the microscopic micron-sized particles being generated. Lower volumes will collect the larger particles that you can see, but will not sweep all the invisible micron sized particles into the DC. [Aside: an interesting theory to confirm/refute with our Dylos particle counters]

To move this massive amount of air, you need as low a resistance "pipe" from your intake point back to your DC as is possible. This resistance is measured as inches of static pressure loss. Bigger ducts have less resistance and allow your DC to move more air (higher CFM) up to a point. That point is limited by the design / power of your DC. So therefore, the bigger the duct the better, right? To some extent, but that's not the whole story.

Although larger ducts have lower resistance than smaller ducts, the larger cross sectional area will cause the air velocity within larger ducts to be slower than for smaller ducts, at any particular CFM (Pipe analogy: for a smaller pipe to fill a bucket as quickly as a larger pipe, the fluid needs to flow faster through the smaller pipe). A limiting factor in any dust collecting system is that you need the air velocity within each duct to be at least 3,500 feet per minute to keep the saw dust and chips suspended in the air. What this translates to in the real world is that you need a minimum air flow of about 400 CFM through a 4 inch duct to keep it clear, 570 CFM through a 5 inch duct, and 700 CFM through a 6 inch duct.

So, as long as your dust collector is capable of moving at least 700 CFM through your particular ducting layout, you would have no problem using 6 inch ducting if your configuration required it (i.e. you need to keep your static pressure loss down because of long runs or multiple right angle turns). With shorter runs such as what you describe, 5 inch ducting should not significantly raise your static pressure loss, so your Delta DC should still have no trouble pulling 700 to 800 CFM. If you don't plan to expand your system in the future, you should be fine with 5 inch ducting. If you are considering extending it or upgrading to a fixed cyclone in the future, then 6 inch main ducting would do no harm.

For those with DCs that cannot move 700 CFM, then ideally you need to design your ductwork with the least amount of static pressure loss possible (shorter run, smoother ducts, no 90 degree turns, etc.) so you can maximize your CFM. Unfortunately, you won't be able to use 6 inch ducting as part of your static pressure diet program.

To calculate your static pressure loss, you can use the tables here. Also, the real world CFM capability of DC's seems to have little relation to what is reported by the manufacturer, which is an idealized CFM without significant static pressure loss. The current DC review in Wood Magazine (March 08) is very good and assesses 15 portable units.

I can't wait to get my 50-760. Another new toy!

Dave

[Chris Stolicky]

As you can see, it really does not seem to be that easy of an answer!

I went back to the Wood magazine article and also ran through the calcs on their Web site. I kind of did a back-of-the-hand rough calc a few days ago.

Here is what I come up with as an absolute worst case (although I'm not sure how I would accomplish this):

For 5" duct (max machine port is 4"):
16' rigid linear
9' for one 90
9' for two 45s

34' x 0.055 SP loss/ft = 1.87"

add 12' of 4" flex: 12' * 3 = 36' x 0.07 SP loss = 2.52" (assuming I can use the SP Loss constant here)

1.87" + 2.52" = 4.39" Total SP Loss [it looks good to me]
According to the graph in Wood Magazine I am good up to 7" SP Loss.

For 6" duct using the same numbers above, I come up with 4.05" Total SP Loss.... not really a big change.

Feel free to check my math. I am known to make mistakes.

I do not plan on upgrading to a cyclone in the future. Even if I ever do decide it is worth the investment, I don't think the 26-gauge metal ducting would hold up!

What I find interesting is that in the Wood article it comments how even those DCs with 6" inlets cannot even support using 6" duct!

Does anyone have any experience or more thought/insight with this unit and ducting?

Thanks again.

[Quesne Ouaques]

Hi Chris:

From both my experience and from experimentation with the 50-760, I can tell you for certain that: (1) the 5" intake does not have a significant effect on static pressure, and that (2) using 6" duct increases the sucking power on longer runs.

Static pressure is caused by the disruption of air molecules on the edge of the main stream of air as they interact with the walls of the conduit. Those disrupted air molecules are "thrown off course", and then interact with -- and slow down -- the molecules in the main stream of air toward the center of the stream. Smooth walls reduce the disruption effect. Corrugation, curves and tight corners exacerbate it. The larger diameter conduit reduces static pressure by reducing the disruption effect of the "off course" molecules.

It may be true that the 50-760 could benefit from a 6" intake, but the simple fact that this DC unit beats the pants off of other 1.5 hp machines that have 6" intakes suggests that the effects from the 5" intake are negligible. The lip of the 5" intake on the 50-760 probably creates some disruption, but it's only 1/4 inch thick so the disruption is very short-lived thus creating very little SP.

According to Sandor, minimum velocity along each route from machine to DC is the most important thing to be concerned with. In other words, as long as the minimum velocity is adequate to keep the chips moving, then you should choose the largest diameter duct possible that will allow you to maintain that velocity.

Before I bought all of the ductwork, I ran some simulation tests with my DC using both a 4" and 6" main. The difference was dramatic with the 6" performing much better. My drops coming off the mains are all 4" which makes for a very straightforward design. When I first set it up, I parked my 13 inch planer about 18 feet away from the DC just to see how it would perform. I have not had to move it! It clears chips without a problem.

Your calculation show an 8.3% decrease in SP -- and thus 8.3% increase in suction power -- using the 6" duct. Personally, I would not disregard this difference as insignificant. When you look at the comparison charts between DC units on FWW and other magazines, small percentages in suction power translate into big advantages in the the real-world shop.