Table Saw Dust Collection Re-thinking

[jteneyck]

I have a Delta 50-760 1.5 HP 1200 CFM collector. I use a Wynn pleated .5 micron filter and not the bag that came with it. It has a 5" port on the collector and I run a 5" hose with a 4" step-down to the separator. From there, everything is 4" with the exception of the OTB guard which is 2.5" I would like to think that at 1200 CFM it should remove a lot of dust. I don't have a lot of extra, unneeded hose, and I go from machine to machine and there is no built in duct work in my small garage space.

I am curious about how much or if I would see any performance upgrade by replacing the foam between my cabinet and the bottom of the table and upgrading to the 4" guard. I have been watching Youtube videos of other table saws in action that have ATB dust collection and they leave very little dust to escape onto the table. I also wonder if by installing the funnel-like insert inside of the cabinet if it will force more free air into the cabinet space and downward out the 4" hose because of the smaller space? I wonder if the large cabinet space under the table is a lot of space for air to just sit??? Kind of like drawing the air through a bathroom versus drawing the air through a bedroom with the same CFM.

Andy

Andy, I doubt you are getting anywhere near 1200 CFM from a 1.5 HP DC.  That's what it may be rated at at the inlet to the DC with no filter on the outlet side, but I would bet money you aren't getting half of that at your table saw.   FWIW, hoses have a lot of pressure drop; smooth piping is far better.  I don't know how long you've had the Wynn filter installed, but they can get completely plugged up with fines if your cyclone isn't removing them.  Actually, they will get plugged up even if it does after enough use.  The first thing I would do is measure the static pressure at the inlet to your cyclone or separator and also in the 4" hose coming out of your TS.  If you have less than 4" H2O at the TS you probably have your answer.  If that's the case, the first thing I would do is remove the Wynn filter and check the static pressure at the TS again.  I think you will need at least 6" to have a chance.   I don't know what kind of cyclone or separator you have, but mine causes a static pressure loss of nearly 4" IIRC, and that could be as big or bigger problem than the filter.  If you aren't getting at least 6" at your TS I would remove the cyclone/separator from the system and check the static pressures again.  The solution depends upon what you find out.  

As I mentioned before, I couldn't get enough SP from my 2 HP DC system at my big bandsaw to evacuate all the sawdust it generates.  It worked fine w/o the add on cyclone but I didn't want to run it that way.  I ended up completely reconfiguring the system with the DC fan now sitting directly on top of the cyclone, like you see with Oneida, etc., and running the exhaust straight out a window with no filter system.  With those changes the SP is now around 6" at the BS and it has no trouble removing the sawdust.  You may need even more SP at your tablesaw because they make often make larger chips than a bandsaw.  

If you don't have a meter or gage to measure static pressure you can make one for the cost of a piece of clear PVC tubing.  

John

[titanxt]

Thank you John, that is a lot of information to digest. Makes me concerned that a DC that is rated for 1200 CFM (thought it likely produces less as you outlined) can not remove the dust properly from a table saw. To be quite honest, I am re-evaluating the use of a table saw in my woodworking because of the dust issue. Though slightly an admitted hypochondriac, I am concerned about it spewing dust all over and the long term effects that it might have on my health.

Andy

[jteneyck]

Thank you John, that is a lot of information to digest. Makes me concerned that a DC that is rated for 1200 CFM (thought it likely produces less as you outlined) can not remove the dust properly from a table saw. To be quite honest, I am re-evaluating the use of a table saw in my woodworking because of the dust issue. Though slightly an admitted hypochondriac, I am concerned about it spewing dust all over and the long term effects that it might have on my health.

Andy

Andy, if you have not already done so you should read some of Bill Pentz's info. related to dust collection.  There is pretty much everything you would ever want to know about dust collection on his website.  It sites several resources that show you can pull the chips out of a tablesaw with 350 CFM, which you can get with one 4" smooth duct, but not flex hose.  But if you want to collect the chips and the fine dust you need at least 750 CFM.  Even TWO 4" smooth ducts will only give you 700 CFM, hoses far less.  Further reading will show that a 1.5 HP, 1100 CFM dust collector is only going to give you 350 CFM with a 4" smooth duct and minimal length ducting and, again, a lot less with flex hose.  

You don't stand much chance of even collecting the chips out of your tablesaw with your dust collector as currently configured, much less the fine dust.  If you are really worried about the health effects of wood dust exposure you should consider installing a much larger DC system, and/or getting a tablesaw with a ducted shroud around its blade, or perhaps moving to a tracksaw hooked up to a HEPA vacuum.  But if you always wear a NIOSH approved respirator you could just stick with what you have.  

John

[titanxt]

I wonder if the home hobbiest even stands a chance to ever collect the appropriate amount of dust. Taking in budget, space, and small shop size machines, is woodworking as a safe hobby out of reach?

[jteneyck]

I wonder if the home hobbiest even stands a chance to ever collect the appropriate amount of dust. Taking in budget, space, and small shop size machines, is woodworking as a safe hobby out of reach?

One would never consider woodworking to be safe unless you work exclusively with hand tools and only some of them, never sand anything, and only use natural oils or waxes or soap finish.  Every machine we use has the potential to do serious harm far quicker than the dust they generate.  

Personally, I am OK with some dust.  I do not personally know one person, hobbiest of pro, who has developed an allergy or cancer from exposure to wood dust.  So I'm pretty sure I'll die from something other than cancer due to exposure to wood dust.  That said, I'm not oblivious to the risk.  I try to collect the obvious stuff, and my DC vents outside so the fines aren't recirculating back into my shop.  I wear a respirator for really nasty chores, like routing MDF or handling some woods that are known to cause allergic reactions.  If I wanted to take additional steps I would hook up my ROS to a HEPA vac.  

If I were truly worried about exposure to wood dust I would only use hand tools.  

John

[fredhargis]

I wonder if the home hobbiest even stands a chance to ever collect the appropriate amount of dust. Taking in budget, space, and small shop size machines, is woodworking as a safe hobby out of reach?

It's almost impossible to catch it all, even with a world class system. For one thing, it won't be hooked to all of your tools like powered hand tools....trying to catch dust from some of the smaller ones is an effort in futility. That doesn't mean you shouldn't try, only that you should set your expectations realistically. The alternative is to follow John's advice on hand tools, or give up the hobby. If you go to the Pentz site ( a good idea if your serious about DC) start with the FAQ section. there's so much material there you could spend days trying to get to what you are really after.

[titanxt]

Good food for thought. I do not use any kind of powered sander inside of my garage. I do all of that outside as my ROS has lousy dust control even when attached to a shopvac (with the HEPA filter I might add....
) My main dust generator is the table saw. I run two lines to by bandsaw and that seems to keep it very clean. I have above and below dust collection on the router table and that seems to work well. The above the table really pulls it in. So, I will spend some more time reading and evaluating how I should go about tweaking the table saw DC some more.

Andy

[titanxt]

From the Pentz site:

"A particle counter shows making a perfect long shaving with a razor-sharp hand plane that makes no visible dust launches millions of fine invisible particles airborne. These fine particles get by our natural protections then lodge deep in our respiratory tissues where they do damage and release toxic chemicals."

Great.... now I am going to have to put DC on my hand planes...

[fredhargis]

Here you go....

[Willyou]

I covered the back of my Delta contractors style saw with a sheet of aluminum with a cut-out shaped to allow the belt and motor mount to swing all the way from 0- to 45 degrees and full up and down depth of cut. This requires quite a sizeable opening. However, I've found that very little sawdust is blown out through this opening. And, I do not have my DC connected to the saw. I use one of the cloth bags hanging from the bottom of the saw to collect all sawdust. It works pretty well. The picture below shows the opening with the motor all the way to the 45 degree angle. With a DC connected, I suspect that air being pulled in through the opening would take care of any dust that now escapes.