Dust Collection and Zero Clearance Inserts

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Forum topic by hokieman posted 06-10-2017 07:03 PM 2284 views 0 times favorited 5 replies Add to Favorites Watch
View hokieman's profile


196 posts in 4364 days

06-10-2017 07:03 PM

I have set up my new dust collection system connected to my Steel City cabinet saw. The dust collection port is at the bottom of the cabinet. The problem I have is there is a lot of dust escaping. Maybe even more that if I didn’t have the dust collector connected. My DC system is a Grizzly 2 hp that moves 1700 CFM. I have a zero clearance insert on the saw. The only thing I can think of is perhaps the zero clearance insert is hindering the capture efficiency. The dust that is escaping is coming from the back side of the blade as it “re-emerges” from under the table back by the splitter. I get better capture with the stock insert but obviously not as good a cut.

Anybody got any thoughts on this and how to correct this? I’d hate to have to not use the zero clearance insert. Thanks for any thoughts.

5 replies so far

View Fred Hargis's profile

Fred Hargis

5929 posts in 3103 days

#1 posted 06-10-2017 07:31 PM

It’s not affecting the DC, except maybe when you trimming the edge off a board. Here’s why: when you’re cutting (even with a normal insert) the workpiece covers all that opening around the blade, so there’s no air moving through that opening anyway. Dust coming off the blade is going to happen, the only way that I know of to catch it is with an overblade pickup, and good airflow. It’s probably still not 100% (I see an occasional bit of dust from mine, but so little it’s negligible. To me that over blade needs to have a minimum of a 3” hose, preferably 4” running to it. There will be some other opinions, this one is just mine.

-- Our village hasn't lost it's idiot, he was elected to congress.

View jonah's profile


2092 posts in 3908 days

#2 posted 06-10-2017 07:47 PM

I could see the insert affecting the dust collection if the port was right under the blade, but at the bottom of the cabinet I don’t think it’s trying to pull air from the insert. More likely it is pulling air from the holes for the cranks or the area around the motor.

You’re probably getting better collection with the stock insert because the dust can swirl and “fall off” the blade as it rotates under the table. I’d recommend an above the table collection solution.

View Redoak49's profile


4356 posts in 2598 days

#3 posted 06-10-2017 08:10 PM

A blade guard with dust collection is about the only way with a zero clearance insert.

I hope people will take a realistic view of their dust collectors and what they can do. There is no way a 2 hp DC will get 1700 cfm or anywhere near that…. maybe half of that. Most of the companies exaggerate their performance and lead the people who buy them completely wrong

I measured my DC and got close to 1700 cfm with 8 feet of 8” duct on a 5 hp with a 15” impeller. You can check my blogs to see what I measured and how I did it.

View AandCstyle's profile


3265 posts in 2867 days

#4 posted 06-10-2017 09:26 PM

Hokie, as Fred mentioned, you need over blade collection. I have a SharkGuard which does a great job. Here is a link to the site. HTH

-- Art

View JBrow's profile


1368 posts in 1530 days

#5 posted 06-11-2017 03:19 AM


I drilled some holes in the zero clearance insert hoping to improve dust collection as well as sealing up some larger openings in the cabinet. My subjective guess is that these steps have helped when using the zero clearance insert but I still get dust on the table.

I drilled a ½” diameter hole just beyond the zero clearance insert infeed slot and one at the rear of the kerf slot. I also added a couple of smaller diameter holes through the kerf. These intermediate holes would be best drilled toward the rear of the insert to preserve the properties of the zero clearance insert no matter the blade height. Of course if a hole lands where the blade meets the wood at the beginning of the cut, the zero clearance insert will act more like the stock insert.

The wide open spaces between the cabinet and the underside of the table were plugged by stuffing upholsters’ foam in this space. The goal was to eliminate the unproductive paths of air entering the cabinet.

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