ZCI & DC?

[MoreToolsForMe]

Hey Folks,
Has anyone here ever drilled holes in table saw throat plates and/or zero clearance inserts to enhance dust collection? At face value, it seems a good idea, but I'm just wondering if my feeble brain is missing some detail that may make it a bad thing to do. I'm thinking like 1/4" holes.
Thanks Folks,
Gene

[Stwood_]

I drilled one 3/4 hole, mainly so I can get a finger in there and remove the insert.
No idea if it helps with the collection. Never gave it any thought.

[®smpr_fi_mac®]

No, it isn't going to help much. Those holes will be covered by the wood running over the holes--no air movement through them.

The dust is moving down as it's being made; the blade is cutting on the underside of the wood. It'll be drawn into the cabinet.

Seal up the cabinet's big holes, such as those around the tilt mechanism and the dust door (if it's missing). There's enough gap between the table and the stand that it won't be starving for air.

(edit)

Dust only comes out the top because it's drawn there by the spinning action of the blade.

[MoreToolsForMe]

No, it isn't going to help much.  Those holes will be covered by the wood running over the holes--no air movement through them.

The dust is moving down as it's being made; the blade is cutting on the underside of the wood.  It'll be drawn into the cabinet.

Seal up the cabinet's big holes, such as those around the tilt mechanism and the dust door (if it's missing).  There's enough gap between the table and the stand that it won't be starving for air.

(edit)

Dust only comes out the top because it's drawn there by the spinning action of the blade.

Yep, I totally get that perspective. It's just that sometimes, even just a small difference could be a huge improvement. My main concern was whether or not I was missing some safety and/or operational hazard or mishap that it could cause. Given that making a ZCI is a fairly cheap and easy operation, if safe enough I may give it a try. It wouldn't be the first time I've just piddled into the wind! 


Thanks folks,
Gene

[TDKPE]

Given that making a ZCI is a fairly cheap and easy operation, if safe enough I may give it a try. It wouldn't be the first time I've just piddled into the wind! 

It might help a little at the end of a cut, when the dust tends to spill out a bit.  If it were me, I'd try it.  Nothing wrong with a ZCI with some holes, as long as they don't make it too flexible.  And you'll improve air flow through those holes a little if you countersink them a bit.  It's going to be marginal to start with, but it's worth fiddling with.  And you can't hurt anything trying it. 

It's what we amateurs who play in our shops for our own amusement do.  


Edit: I should add, I doubt is will make a noticeable difference.  But I'd still try it. 

[EvilTwin]

The most effective DC in a table saw would be a shroud around the blade. That would collect it as it's generated and not let it fall out of the airflow to sit on the bottom. Catching it as its made on the top by a blade guard would also be a big help. That is what you tend to see on lots of the more recent Euro machines, hard to do as a retrofit on something like a Unisaw.

I've never had all that much luck retrofitting DC to any tools I've had, and its not for a lack of trying.

[MoreToolsForMe]

All fantastic observations, point and ideas from all! 
 While I'm well aware that an overhead guard with DC attached is the ideal, I'm looking to improve the situation (even a little bit) when performing operations which require the careful use of the saw with no guard in place, such as certain dadoes and finger joints, etc.

Thanks Again For The Great Replies & Insights,
Gene

[Alan in little Washington]

Some ok and some not so ok info in this thread.

1.  Holes in the throat plate won't do squat- they'll be covered up by the wood. They are too small for a relatively low SP of a typical dust collector to draw much air through them.
2. DO NOT block off cabinet openings- that prevents make-up air from entering the cabinet which inhibits air flow and dust collection there.
3.  NO DC on the market has enough suction to keep dust in the cabinet and preventing it from coming up around the blade and off the teeth of the blade.
4.  You need a DC shroud to pick up above-table dust.  During the cutting process, dust gets caught in the blade gullets and is carried along with the blade.  A portion of it is thrown from the top of the blade at greater than 100 MPH!  (10" blade @ 3450 rpm) You need a physical barrier to kill the inertial of the high speed dust, i.e. to stop it from being thrown at you and into the air, and contain it so it can be sucked up by the DC hose connected to the shroud.  The shroud must also allow for make-up air to enter, or else you won't get flow.  Here is one possible solution:

[EvilTwin]

Interesting idea for the overhead dc.  Only thing I would not be sure about is that you would not be able to see the actual cut through all the brush fibers.  If there is no splitter behind the blade and the cut were to bind, you would not see it since that obscures the view all the way back.

[MichaelMouse]

Some ok and some not so ok info in this thread.

1.  Holes in the throat plate won't do squat- they'll be covered up by the wood. They are too small for a relatively low SP of a typical dust collector to draw much air through them.
2. DO NOT block off cabinet openings- that prevents make-up air from entering the cabinet which inhibits air flow and  dust collection there.
3.  NO DC on the market has enough suction to keep air in the cabinet and preventing it from coming up around the blade and off the teeth of the blade.
4.  You need a DC shroud to pick up above-table dust.  During the cutting process, dust gets caught in the blade gullets and is carried along with the blade.  A portion of it is thrown from the top of the blade at greater than 100 MPH!  (10" blade @ 3450 rpm) You need a physical barrier to kill the inertial of the high speed dust, i.e. to stop it from being thrown at you and into the air, and contain it so it can be sucked up by the DC hose connected to the shroud.  The shroud must also allow for make-up air to enter, or else you won't get flow.  Here is one possible solution:

Guess you're doing a lot of work with crosscut-type blades with virtually no gullets.  I use mostly combo blades, which have ample gullet room to carry.  They get flung downward by the combination of gravity and centrifugal velocity.  
Truth to tell, I don't get much sawdust laying on the wood even when using 80-90 tooth blades for crosscutting.  I do, however, use the old method of keeping the blade low.  Loss of visibility and splitter outweighs the stuff that might run up.  Guess a dust mask would do, if there was much.  
Now burning resin fumes when cutting some softwoods - 'nother matter.