Dust collection question?

[keith micinski]

So, I just got my new Harbor freight dust collection set up on my new G1023 and I have a few questions. Because of an issue with the throat insert that Grizzly sent with the saw I had to make my own Zero clearance insert and it seems like this is hurting my dust collection a little bit because there is really no way for air to suck through. Does this make sense? Also if I cut a piece and just trim off a little amount while leaving the left side of the blade open I get an enormous amount of dust coming out of the blade right at me. Is this normal and would a regular throat insert allow more air flow and improve my suction?

[Prashun Patel]

Some people have had success elongating the opening behind the blade.

[Dan Friedrichs]

Really, it's awfully hard to draw a fast enough stream of air into your sawblade to knock the dust out and towards your dust collector. You need to first stop the dust from moving, then use a large volume of air to move it away. Overarm dust collectors do that by providing a hard plastic surface that the dust first hits as it flys off the blade, which effectively stops it from moving, then the velocity of the moving DC air is enough to move it away.

So you need overarm dust collection.

Alternatively, I've found that the height of the blade above the wood makes a huge difference in how much dust gets thrown. Raise it a little more than you usually would, and you may find a great improvement.

[Cliff Holmes]

This is a really common issue, when the blade side is exposed there's no channel to route the dust downward. I'm not sure how effective it is, but I like the way the Powermatic 2000's blade guard uses two independent sides that rotate up parallel to the table. That way, if only one side of the guard is on the wood, the other side stays on the table. I think my SawStop's guard dust collection would be much more effective if it used this design. Instead, the side's pivot point is at the front of the guard, right where it's trying to collect the sawdust, so it's open at the worst possible point.

[keith micinski]

Well Cliff, I have a little bad news on the blade guard front. My saw also came with a blade guard that has two sides that go up and down independently and two be honest with you somehow it didn't make an ounce of difference on dust collection when I put it on. I also know about not having the blade too high. Grizzly is supposed to be sending me a new zero clearance insert and once I get it I am going to open up the throat insert I made a little. I cant really open up my insert towards the back because the riving knife and splitter take up all of that space.

[David Christopher]

Keith, I just drilled some small holes near the front of the blade slot and it works alot better

[Prashun Patel]

The Sharkguard is a great value if you want to improve yr above table dust collection.

[keith micinski]

Dave that's not a bad idea. A new overhead dust collection guard is a long way off in the future so I will gibe drilling the holes a shot.

[Joe Leigh]

I don't think it's a good idea to drill the holes. The fact is that the shroud only covers a portion of the blade (lower half) and that leaves quite a bit of open space between the upper half of the blade and the table insert. The dust collector will not pull any air from the insert with all that available area to draw from below the table. I keep a ZCI on my Powermatic PM2000 full time, and when used with the saw guard for ripping operations I get nearly zero dust above the table and I only have a 1hp DC.
It's been said a hundred times here, and I now know it to be true, the only way to eliminate MOST of the dust above the table level is with overblade dust collection.

[keith micinski]

My saw has a shroud around the underside of the blade that pulls most of the air from right there at the throat opening. A few holes would increase the air flow and wouldn't hurt anything if they don't work anyway. I know that you are not going to be able to eliminate above the table dust but I am pretty sure I have low flow air issue when I have my zero clearance insert in. I'll drill the holes today and see.

[david brum]

Also if I cut a piece and just trim off a little amount while leaving the left side of the blade open I get an enormous amount of dust coming out of the blade right at me. Is this normal and would a regular throat insert allow more air flow and improve my suction?

I don't think anybody addressed this question. This is normal and will happen regardless of how much dust collection you've got. Trimming anything less than the width of the blade will create a jet of sawdust which will spray all over the table. Lots of folks try to leave, say, at least 1/4" of extra material before they make a rip. Much cleaner that way.

On the subject of Zero clearance inserts, they are mainly for crosscuts, where you want the insert to hug the blade in order to cut the wood fibers cleanly. On a rip cut, you usually only need the insert to be close enough to the blade to keep any offcuts from jamming between the blade and insert. I usually use the stock insert when ripping.
Having a wider slot or some holes isn't a bad thing and definitely helps with dust collection. You're right that the air has to have somewhere to go. When you think about it, you're reducing a 4" hose to a 1/64" hole, so you can't expect to get any airflow. You need some makeup air to make the system work.

Since you're making your own inserts, you might want to make up a bunch and experiment with what works the best. You can make a wider slot with a dado blade, router, etc.

Of course, having a bigger/wider slot won't help with above table dust collection. You still need some type of overhead system for that. It does help until you can budget for something though.

[keith micinski]

Thanks Dave that's what I was looking for. I had a feeling there was no way to control that dust to the left of the blade when it was left open but my contractors saw never had that much dust come out. I am probably going to get around to experimenting with making my own inserts but I have other more pressing projects to get done right now.

[Joe Leigh]

Not sure what the shroud looks like on the new 1023 but here's a good pic of my shroud...

http://i137.photobucket.com/albums/q226/lj61673/New%20Saw/DSCN1740.jpg

As you can see there's a lot of room between the top of the shroud and the underside of the table top. Doesn't matter how many holes I drill the DC is going to pull air from this open area before it pulls from holes in the insert.

[Chris Parks]

The trouble is lack of air. A dust collector has the capacity to draw a given amount of air through the duct. To do that you must supply it with the same amount of air. By installing a ZCI you reduced the amount of air that can enter the cabinet so the dust won't follow the air as the air is not flowing towards the dust collector. Even with the standard insert the amount of air getting to the collector was most probably not enough and you need some way to get extra air and that entails openings into the cabinet. How you do that is up to you, I just left the original hole for the dust collection open and made another for the duct to connect to.