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Improving table saw dust collection w/zero clearance insert

6K views 21 replies 11 participants last post by  diverlloyd 
#1 · (Edited by Moderator)
Has anyone drilled holes in their zero clearance insert to improve dust collection? I've noticed that I get better collection with the stock insert because of the larger opening. Just wondering if theres been any success with this done.
 
#3 ·
All the dust you can capture is in the blade gullet with a ZCI. How is reducing the suction (by adding air) going to increase the vacuum?

M

- MadMark
Dust doesn't get directed into the dust collector because of a vacuum. It's directed there by airflow and if there is not a path for make-up air to enter into the cabinet, then the dust collector is choked off and becomes less efficient.

If the air can come in from the side of the blade and down, then that will help direct the dust downwards, towards the collection hose rather than being flung up and around the blade and into the air. A ZCI is to help the quality of the cut and has nothing to do with dust collection. It will actually hinder the airflow. Any makeup air has to come from below the table, or the side and thus will cause the airflow to counter the flow you would want.
 
#4 ·
But when the saw is making dust isn't the insert covered by the workpiece (?) (unless your cleaning up an edge.) I see this suggestion often and can't help but wonder about it's usefulness. I just switch to the factory insert if I'm cleaning up an edge.
 
#5 · (Edited by Moderator)
I don't know how effective it is, but the theory of drawing in extra air from the insert seems logical to me, as long as there's suction coming from below. Most of my ZCI's have an extra hole cut just in front of the blade (in addition to the finger hole), in hopes of getting a little extra downward dust flow there.


 
#7 · (Edited by Moderator)
But when the saw is making dust isn t the insert covered by the workpiece (?) (unless your cleaning up an edge.) I see this suggestion often and can t help but wonder about it s usefulness. I just switch to the factory insert if I m cleaning up an edge.

- Fred Hargis
I see what you mean. Hmmm. I guess overhead collection is the best way to get the extra dust.
 
#9 ·
But when the saw is making dust isn t the insert covered by the workpiece (?) (unless your cleaning up an edge.) I see this suggestion often and can t help but wonder about it s usefulness. I just switch to the factory insert if I m cleaning up an edge.

- Fred Hargis
You're right. I did have that typed in there that unless you're cutting an edge, air is blocked regardless of whether you have holes or not. It was late and as I was editing my post, I deleted all that part. Nice catch, haha.

And definitely an overhead collection point is needed, especially with the ZCI.
 
#11 ·
Overhead dust collection with a ZCI esp. with a buried cut, is useless. The rising back of the blade doesn't bring sawdust up. Only the leading edge cuts & makes dust. When it's cutting the gullet is buried and is the only place that the dust can go. As the gullets open below the table centrifical force & gravity clean the gullet for the next go-round.

AZ its the VACUUM that moves the air. After all you don't connect the saw to a blower

M
 
#13 ·
Overhead dust collection with a ZCI esp. with a buried cut, is useless. The rising back of the blade doesn t bring sawdust up. Only the leading edge cuts & makes dust. When it s cutting the gullet is buried and is the only place that the dust can go. As the gullets open below the table centrifical force & gravity clean the gullet for the next go-round.

AZ its the VACUUM that moves the air. After all you don t connect the saw to a blower

M

- MadMark
And your point is what, Don't do it at all? Or don't do it because for cutting strips it won't work? Which is maybe 5% of TS use for most people?
 
#14 ·
Overhead dust collection with a ZCI esp. with a buried cut, is useless. The rising back of the blade doesn t bring sawdust up. Only the leading edge cuts & makes dust. When it s cutting the gullet is buried and is the only place that the dust can go. As the gullets open below the table centrifical force & gravity clean the gullet for the next go-round.

AZ its the VACUUM that moves the air. After all you don t connect the saw to a blower

M

- MadMark
And your point is what, Don t do it at all? Or don t do it because for cutting strips it won t work? Which is maybe 5% of TS use for most people?

- rwe2156
He never has a point. He makes up one situation which was not even mentioned by the OP to show where it won't help and then says that's the reason it's not ever needed.

You can tell how clueless he is when he doesn't realize that a dust collector IS a blower…

One thing I wish this forum had was an ignore mode so a person's posts wouldn't have to be seen.
 
#16 ·
Overhead dust collection with a ZCI esp. with a buried cut, is useless. The rising back of the blade doesn t bring sawdust up. Only the leading edge cuts & makes dust. When it s cutting the gullet is buried and is the only place that the dust can go. As the gullets open below the table centrifical force & gravity clean the gullet for the next go-round.

AZ its the VACUUM that moves the air. After all you don t connect the saw to a blower

M

- MadMark
And your point is what, Don t do it at all? Or don t do it because for cutting strips it won t work? Which is maybe 5% of TS use for most people?

- rwe2156

He never has a point. He makes up one situation which was not even mentioned by the OP to show where it won t help and then says that s the reason it s not ever needed.

You can tell how clueless he is when he doesn t realize that a dust collector IS a blower…

One thing I wish this forum had was an ignore mode so a person s posts wouldn t have to be seen.

- AZWoody
Hahaha. Bingo!
 
#17 · (Edited by Moderator)
At least I'm not posting 'inspirational' garbage pail 'projects' ...

You know not what you don't know and you use every post to prove the point.

You don't say why I'm wrong, just that I'm wrong. You sound like Hillary.

You replace the brand new saw top for 'scratches' & try to sell the bad one. You think its a good idea to store your safety gear away from the saw. You are a completely non-self aware idiot.

My sympathies for you family due to your pending saw accident.

M
 
#18 ·
As noted, above, at least a couple of us use Excalibur over-arm guards with dust collection. Generally, this means the collector is both pulling from the cabinet and above the cut. As such, we have first hand experience using them.

Except when making dados or rabbits, I always run ZCI's. When making thru cuts and without the over-arm collection in play, I get a lot of dust on the floor, in front of the saw. With it, I get very little, if any.

For reference, the lower collection port draws not just from the throat plate, but also from the top, where the table bolts to the cabinet, from the two adjustment wheels and at the top back, where the mount for my Merlin Splitter connects. I did silicone the inside, where the metal bottom connects to the cabinet and directs sawdust to the bottom port.

When running for my table saw, my three horse, four bagger is drawing from two four inch lines, one on top and one on the bottom.

Wood Flooring Composite material Gas Hardwood
 

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#19 · (Edited by Moderator)
One thing I wish this forum had was an ignore mode so a person s posts wouldn t have to be seen.

- AZWoody
I thought we had that. Go to his profile and click the "block" button (?). Seems like I used it once and the individual only showed up when he made a new post, replies did not show (I think). On another forum I participate, we refer to that action as "gumping"...as in "I gumped that name".
 
#20 ·
One thing I wish this forum had was an ignore mode so a person s posts wouldn t have to be seen.

- AZWoody

I thought we had that. Go to his profile and click the "block" button (?). Seems like I used it once and the individual only showed up when he made a new post, replies did not show (I think). On another forum I participate, we refer to that action as "gumping"...as in "I gumped that name".

- Fred Hargis
Sweet! Thanks! Done. I hate when someone only has negative things to say. They THINK they know it all. Not helpful at all!
 
#21 ·
Woodchuck2010,

I am puzzling through the same issue, effective below the table dust collection with a zero clearance insert. I am aware of various overhead dust collection hoods, but do not like the idea of adding stuff over the blade, though it will probably yield the easiest and maybe even the best table saw dust collection; especially when coupled with below the table dust collection. While I cannot provide a prescription for effective below the table dust collection with a zero clearance insert, I can share the results of my efforts and my thoughts thus far.

I am using a 5hp dust collector with two 4" dust ports pulling air out of the table saw cabinet. The cabinet is mostly sealed with upholsters foam stuffed in the voids between the cabinet and the underside of the table and around the motor cover. I also sealed the large slots in the cabinet that allows for tilting the blade. With a zero clearance insert, I noticed a drop in dust collection air flow as measured by the shop made manometer, so I re-opened the cabinet's tilting slots in front of and behind the trunnion.

Like knotscott, I drilled a ½" hole at the end of the kerf on the infeed end of the insert. That seemed to make a difference, allowing for better dust collection. However, dust sometimes spews out across the table. I then added a hole at the outfeed end of kerf. Then I elongated the added infeed hole into a slot running perpendicular to the blade. Since I always keep the factory guard in place for through cuts, I also closed off the side guards. I do not believe that the hole at the outfeed end of the kerf nor closing off the side guards on the factory guard made much difference. So far I remain dissatisfied with dust collection.

I suspect under the table baffles to channel air flow would enhance dust collection. Therefore, plan to configure some baffles below the table in an effort to better direct air flow past the blade toward the dust collection ports. I am also thinking about whether a baffle could be designed that perhaps could dislodge some of the dust that is not otherwise cleared from the saw blade's gullet while the gullet is under the table

I also plan to drill a series of holes centered on the kerf in the zero clearance to increase air flow along each sides of the blade. I am thinking this will prove especially beneficial for skim cut dust collection.
 
#22 ·
Dust collection works by suction not vacuum, but that's just terminology. To much suction causes a vaccum that's why if you seal up your saw to well the dust collection doesn't work very well. You need air flow kind of like when your dust collector filter is clogged it didn't work because you have no air flow. I think of the collection system as a hvac system( I used to have my masters license) air flow good vacuum bad. To much of either is bad like anything else in life.

I do like the design of the zci with the holes in the end of the slots I think I will be drill all of mine like that from now on. Drill some more hole and let us know how it goes I'm interested in what would happen.
 
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