Improving dust collection from Kapex SCMS - Need help with overkill method

[Alan Lightstone]

This is one of my big pet peeves. Dust collection from my Kapex miter saw is terrible. And, supposedly, it's much better than competing models.

So, in my typical overkill fashion, I've been working on a solution.

I bought and installed a Rockler 1250CFM dust collector, and with tons of help installed it on the wall. It's got 6" flexible duct attached to it.

My present setup is with a Festool Mini shop vac with 36mm hose attached. Lots of wood dust scatters on the floor in front of the saw, as well as tons behind and around the saw.

I'm going to build some type of enclosure around the Kapex, and hook that up to the dust collector. Lots of videos on this on Youtube. Some good, some awful. None are taking this approach, because they're sane.

Which would be the preferred approach?

1.) Splitting the 6" dust collector hose into two 4" hoses, one for the Kapex shoot, and one for the box around it.
2.) Continuing to use the Festool vac for the dust shoot and using the 6" hose to connect to a box around the Kapex, so using both.
3.) Any other thoughts?

I know the shop vac will provide more static pressure and the dust collector far more CFM.

[Jim Becker]

My opinion is that you should still be using collection from the vac to the tool's dust port.

Check out Jay Bates' miter station on the 'Tube for a good method for a surround for the tool so you can utilize the DC for catching the 'splash' which is the nature of any miter saw.

[Aaron Inami]

Not sure if a Rockler 1250CFM is enough, but I have a friend who built a down-draft table which the Kapex sits upon. Combined with the normal Kapex dust collection, it works extremely well.

[Rob Sack]

I've mentioned this before on the Forum. I too have a Kapex and felt that having to invest in a Festool "Extractor" with the appropriate Festool hose, setting me back somewhere between $800 and $900+, was out of the question. After doing some research, I found a Ridgid Shop Vac, Model No. WD7000, from (Ugh!) Home Depot along with a proper 35 mm Bosch hose from Amazon and an automatic vacuum switch also from Amazon. I was able to demo the Festool Kapex with the recommended $800+ Extractor set up at AWFS. In all fairness, the combination was rather effective. As near as I can tell, my set up works just about as well for less then half the cost. Dust collection seems to be on par and my vacuum goes on automatically when I turn on the saw. As a bonus, my shop vac can be used as an actual wet/dry vacuum if I choose, unlike the Festool Extractors and comes with a limited life time warranty, also unlike the Festool Dust Extractors.

[Aaron Inami]

In response to Rob's comments, I can definitely see how the Rigid shop vac is giving better performance compared to a Festool dust extractor when using it for the Kapex stock dust ports. The Rigid shopvac will have significantly higher CFM, somewhere in the 180-200 CFM range depending on who you talk to. This is because the intake filter on the Rigid has significantly more surface area than the Festool dust extractor and there is no bag/filter on the Rigid (though this makes it more of a hassle to clean out the debris/sawdust from the Rigid).

The Festool excels on other devices because you can adjust the suction using a dial and the Festool design will produce consistent suction/CFM even when the filter/bag fills up. The CFM on the Festool is tested to range between 130 and 159 CFM (wide open). Once you start using the 36mm hose, it will actually drop down. Using larger diameter hoses will reduce the amount of hose restriction on the CFM.

You could try getting a 50mm hose on the Festool (with reducer) and trying that with the stock dust port on the Kapex:

https://www.festoolusa.com/accessory...--d-50x2,5m-as

https://www.festoolusa.com/accessory...36-as#Overview

Or get a shopvac if you don't want to build a dust collection cabinet/downdraft for the Kapex.

The Rockler 1250CFM dust collector will do almost nothing if you reduce it down to a 1-1/2" or a 2" hose connection.

[Ron Selzer]

no 2 sounds like the best option to me, let us know how it turns out
Ron

[Andrew More]

#2 - This is pretty much how I have mine setup, after years of looking into the issue. Essentially the problem is you've got a blade moving at 100+ MPH, you _might_ be able to get the DC/shop vac to run at 40 at the edge of the outlet. I know of no way to get that close to the blade. The ports on most miter saws get closer than you can with an outlet from the DC, but you can't really get good suction from a DC through one, because of the small port, so a shop vac is necessary.

So the dust is going to get flung in whatever direction it's going to go.

The good news is just like flinging a hand full of snow, it's not going to go far, but it's going to be enough to make a mess around the saw, and there is no solution to this. The other good news is that the blade flings things back from the saw, which is why the box is a good idea. Also running the DC into the box seems to capture most of the fine particles, which are the main safety hazard. You might also be able to improve the performance from the shop vac port with a better scoop, I've got the Shop Nation one attached to my Bosch.

One other minor point, I think a dust extractor is total overkill for this problem, unless you've already got one. Personally I like the Dewalt stealth sonic shop vacs, because they're super quiet, but really any cheap shop vac will do. If you must have the auto-on, you can get an adapter for that for like $30, and save some money.

[Aaron Inami]

I had been recommending the Dewalt stealthsonic to people because of noise. Looking further, I think I need to retract my recommendations.

Be aware that the quietness of the Dewalt stealthsonic comes at a price on CFM. Actual CFM on these stealthsonics are in the 90-105 CFM range depending on model. This is actually less than any Festool extractor!!

The Fein and Bosch vacuums do much better at 150 CFM ratings. There are some Rigid "shopvac" style vacuums that indicate 170-180 CFM, but these are likely to be the extremely loud and annoying models.

[Kevin Jenness]

I have a shroud around the miter saw made of 3/4" ply decks and a bending ply back with a 5" DC drop in the bottom deck which works well. It wouldn't hurt to have a separate shop vac on the tool but it seems redundant. It would help a bit on wide cuts where the exhaust is in front of the shroud. I use the stock filter bag which helps in that scenario.

[Rob Sack]

There are some Rigid "shopvac" style vacuums that indicate 170-180 CFM, but these are likely to be the extremely loud and annoying models.

The Ridgid shop vac I am using is rated at close to 200CFM and as far as noise is concerned, is significantly quieter than either of my Craftsman shop vacs. However, the Ridgid is louder than the Festools I tested and would have to be louder than the new, quieter Dewalts.

[Michael Burnside]

Alan, sane or insane, doesn't matter, it's your shop and your money. You might find the 1250 works great for something that surrounds the Kapex, but you'll probably end up still needing the Festool vac attached to the dust port of the saw. I don't think the 1250 can give you the CFM you need at the tool.

Having said that, if you want truly overkill, I occasionally attach my Oneida Supercell to the Kapex port and have a couple wings funneling towards the back and I get little to no dust. The Oneida is probably close to 4-5x what the 1250 can do on a 2.5" hose (I have both, I know) and they are not even comparable. The Oneida is a monster, but it's overkill at 2700 bucks

Unless I'm cutting a lot of material, which I rarely do on my Kapex (I prefer the Carvex), I'll just hook up my Festool CT-26 with a 36mm hose (1.5 meters long) and it works pretty well with my setup. I'll try to send a picture of the setup sometime.

[Alan Lightstone]

I actually have a 5HP Oneida, but due to my design mistakes with cabinets, and having to rout the metal ducting upwards to the Kapex in an area where it would be very difficult, I took this route. Wouldn't have been a cheap solution for the Nordfab for that either. I have no doubt that the Oneida cyclone could do the job (at least on the outside shroud, perhaps not on the inside dust shoot of the Kapex).

I'm working on a wood shroud to cover the Kapex, but still allow for 45° cuts by allowing removable pieces (similar to approaches Jay Bates, Fisher's Shop, DIY Montreal and others have posted on YouTube videos. I'm thinking of holding the front pieces on with rare-earth magnets, as I think that would be the easiest to remove for the 45° cuts. The first job I am working on is filling up the gap below the back of the Kapex, as dust always fills up back there, as well as to the sides of it.

I'm really thinking this won't do enough to prevent the dust that sprays out in front of the saw on the floor. We'll see.

[Jim Becker]

Having a dedicated collector for the miter station isn't unusual and it can be effective if you build in the necessary "controls" to contain the stuff spewing off the blade so it can be collected.

[Chris Parks]

For a start that 1250CFM is not 1250 as every manufacturer embellishes their flow numbers but a very few do not state them because measuring flow is like rounding up a herd of cats.

A saw, any saw generates both fine and heavy dust and mitre saws are one tool that have to be in a housing and a very high flow extractor used to capture the fine dust. The standard port captures the heavier dust to some extent but the fine dust that results from cutting does not get captured very effectively and ends up floating around the operator which is not good. My mitre saw is in a housing that comes back to the fence and the extraction is done by a CV1800 running at 75hz and it still does not capture all the fine dust just most of it.

Alan, I know you are very aware of dust issues but mitre saws are a very difficult tool to effectively capture all the dust. There are a large number of videos on YT but most of them do not use a big enough DE and very few of them use 6" ducting which is the absolute minimum and given a capable extractor a larger diameter would be better.

[Allan Dozier]

IMG_8326.jpgIMG_8322.jpgIMG_8325.jpgIMG_8323.jpgI am looking for suggestions too. Here is what I have so far but I was planning on building some sort of hood to try to catch more. I have a 5 hp Clearvue and my miter saw is directly on the end of the 7" run. As you can see the smaller hose Ys off and attaches to the Kapex. So I get a good bit of flow but still get sawdust scattered on the base and the floor. The other thing I think may help is that I usually pull the saw like a radial arm saw unless I am cutting small width boards. I think this tends to direct more sawdust back to the rear where the round duct opening is behind the saw. I know this is not how it is recommended but I've done it for years. The flex duct goes to a floor sweep which I don't use that often and stays closed.