zero-cleearance insert and dust collection?

[Zach England]

My biggest dust problem is still the dust that never goes into the saw cabinet. I seem to recall seeing something once about a certain way to construct an insert to maximize the amount of dust that gets pulled down into the saw, but I cannot find it and cannot remember how it worked.

I am looking for a simple aid in this until I come up with the energy to construct a vacuum-equipped guard. Any tips?

Thanks.

[Rick Moyer]

I drilled a bunch of holes in mine. Helps but not fantastic.

[Fred Hargis]

I keep thinking that even with extra holes in the insert, most of the time when you're cutting they will be covered by the workpiece. I don't see how they would help (just an opinion). I can see benefit if you were just trimming the edge, but otherwise the solution I went with was an overblade connection to the DC. I went with the Sharkguard, but any of them are (probably) better than none at all.

[James Baker SD]

somebody on this forum had a photo of a zero clearance insert with the slot at the back of the blade widened. Still gives full support where the blade is cutting and the kerf in the workpiece did not completely block it off.

James

[Bruce Wrenn]

In a recent article in FWW on dust proofing TS, author drilled a couple of holes in rear of ZCI. But your board covers these, so their ability to collect dust is limited, IMHO.

[glenn bradley]

somebody on this forum had a photo of a zero clearance insert with the slot at the back of the blade widened. Still gives full support where the blade is cutting and the kerf in the workpiece did not completely block it off.

James

That would be me. I read the tip somewhere just a few months ago. I cut the rear 2" or so of the slot 1/4" wide. It is definitely a noticeable improvement.

http://www.sawmillcreek.org/attachment.php?attachmentid=125494&d=1250441619

I cannot use the overarm dust hood when I use the sleds so I leave the throat plate out whenever I use a sled and this seems to really help with the stuff that used to get carried onto the sled surface.

[Salem Ganzhorn]

I don't get much dust on the top of the table when ripping. But when trimming an edge I get a huge amount. In this case holes may help. But really I think overhead dust collection with a blade guard is the solution.

[John Thompson]

Having tried holes in inserts which get covered by the stock. I knew that and tried anyway... :)... my conclussion was that the only significant way to reduce the dust that doesn't get feed down with help from the gullets is an over-head pick-up. After adding one I get about 90%-95% efficiency.

BTW.. one way that may help is to use a proper rip blade when ripping as you have more gullets to help carry waste down. A blade with more teeth and shallow gullets is just going to leave more on top of the table. Cross-cutting is not a real problem with higher tooth count and you are usully limited on stock width so the cut area is much less.

[Philip Rodriquez]

I agree with Sarge.

First, make sure you are using the right blade and try ripping with your stock blade guard. Depending on the design of the guard, you may see some improvement.

Second, make sure you have a dust collector that is giving you all you need. IMHO, 1 HP units do an okay job on the big stuff but they do not pull enough to collect the fine dust. A 1.5 unit would make a big deference.

Third, an overhead collection point will, as Sarge said, make a huge improvement (if your DC will support two hookups). I'd guess a 95% to 99% improvement.

[Zach England]

The widening of the slot in the last two inches was the thing I was looking for. Thanks, all. I will give it a try. I guess the hollow chisel mortiser would be the best way to do this? I think I have a 1/4 or 3/8 mortise bit. Barring that I could use a *gasp* hand tool.

[Rick Moyer]

I don't get much dust on the top of the table when ripping. But when trimming an edge I get a huge amount. In this case holes may help. But really I think overhead dust collection with a blade guard is the solution.

Exactly, that was my point. The holes help some. When ripping, the throat is covered whether you have a regular OR zc insert. Overhead seems to be the best way to accomplish better dust collection.

[Zach England]

I agree with Sarge.

First, make sure you are using the right blade and try ripping with your stock blade guard. Depending on the design of the guard, you may see some improvement.

Second, make sure you have a dust collector that is giving you all you need. IMHO, 1 HP units do an okay job on the big stuff but they do not pull enough to collect the fine dust. A 1.5 unit would make a big deference.

Third, an overhead collection point will, as Sarge said, make a huge improvement (if your DC will support two hookups). I'd guess a 95% to 99% improvement.

My DC is 2 HP and the table saw is on a dedicated run, but the problem lies as much in the design on the jet cabinets as anything. This is the subject of a forthcoming question.

[Alan Schaffter]

What kind of DC are you running? You need a good DC to get dust from a TS. Also, don't make the mistake that many folks and that is to tightly seal the cabinet- you need good air flow for the DC to work. Seal around the elevation and tilt wheel openings if you want but don't seal the table to the cabinet to allow take-up air to enter. If you want, add a piece of duct inside the cabinet from an opening to near the blade to direct take-up air directly at the blade.

Lastly, use an overblade dust pickup like the one I built. It allows me to use it most of the time except with all but large jigs and weird fixtures when I must fold it up out of the way. The overblade pickup must also have good suction meaning you need a good DC with 6" duct to the saw's cabinet and 3" - 4" to the overblade pickup. The pickup doesn't need to be solid, it just needs to deflect the dust coming off the blade until it is taken up by the air flow. With soft bristle sides my pickup stays on or close to the table or wood when in use.


More pics. (http://www.ncwoodworker.net/pp/showgallery.php?cat=1403)

http://www.ncwoodworker.net/pp/data/1403/medium/PB050012.JPG