I test 3 cut techniques to find optimal dust extraction on a Festool Kapex

[AofD]

Festool Kapex dust extraction is great!  I test 3 basic cut techniques to find the optimal dust extraction.  It's not scientific but the empirical observations reveal which one might be best.  I use a thermal infrared camera to help observe the dust spray cone.

 

[woodbutcherbower]

That's a great video - and thanks for taking the time and trouble to make it. My saw is a Dewalt 780, not well-known for it's quality of dust extraction (it's hopeless, actually). I carried out the same experiment as you many years ago, and my findings were exactly the same as yours.

 

[dicktill]

WOW, thanks for the info and the effort!

 

[ChuckS]

Very cool thermal clip! I use all three of the cutting methods, depending on the task at hand.

The first (scribe) cuts were similar to trenching cuts (dadoes), which I usually find a dusty operation. When I do a lot of trenching cuts, I install the stached rubber shroud to improve dust extraction.

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The third type (slide all the way back) is what I use by default with my Kapex, since my boards are 4" and wider in most cases.

Now and then, I go with the second type of cut (the chop cut) when I use the CMS as a chopsaw in making a large quantity of narrow cross-cuts for efficiency rather dust collection consideration. Yesterday, I just did that on the Kapex to make some 150 pieces with 1x2 material for a project. Chop cuts are about 2 times faster than sliding ones.

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[Cheese]

Thanks for the video ......that really does an excellent job in highlighting the cleanest cutting method.

What did you use for a dust extractor and what hose diameter did you use?

 

[AofD]

Thanks for the love.

[member=75780]woodbutcherbower[/member] , I figured others were equally curious and already found the answer [wink].  It's good to know we came to a similar conclusion!

[member=57948]ChuckS[/member] ,  I agree.  Despite my findings, I'm likely going to adapt cut technique depending on the task.  Previous to this experiment, my default was to scribe and cut but now, I'll default to a "single-pass slide".  BTW, I made up the cut technique names.  I couldn't find anything on the internet, so I chose names that seemed descriptive.  Hahaha.

[member=44099]Cheese[/member] , I used the larger 36mm hose with my CT26.

 

[Mortiser]

[member=16521]AofD[/member] , this is a very informative video. Thanks for making that and sharing it. I've used all of these techniques (I think your descriptions are well named) and I will definitely default to the single-pass method unless I have a need to use one of the other ones.
I wonder if Festool has done this to evaluate dust collection. If not, I hope they'll take note of this.

 

[AofD]

[member=39410]Mortiser[/member] , given the solid design, I suspect Festool has other adequate means to evaluate dust collection efficiency.  I bet they model and simulate the dust output to optimize the design then test with prototypes and iterate as needed.  They might have a good way to evaluate the dust output with a high-speed camera, special lighting and a dark background to bring out the best contrast.  It turns out that using a thermal camera is very good at "seeing" the dust stream so it could be a new tool for them.

I also contemplated using video processing on the thermal infrared images to quantify the volume of missed particles using Matlab.  That was overly ambitious this time around.  Maybe for another time!

 

[usernumber1]

thanks this is fantastic.

i'm curious how this compares to taller pieces like crown molding, etc. also how much does a saw stache help?

 

[semenza]

Would love to see this on wide boards on the flat.

Seth

 

[Peter_C]

Thanks for the video

Now what technique produces the best overall cut quality?

I run my Bosch miter saw that has a DIY PVC dust guard with a D36 hose hooked up and a dust hood connected to a 4" hose. Catches most of the escaped dust to the point my dust meter barely changes readings. Even a Kapex can utilize a dust hood for better dust collection.

 

[woodbutcherbower]

Now what technique produces the best overall cut quality?

For me -  it's the technique of putting a new blade on the saw  [big grin]

 

[ChuckS]

The combined use of the ZCF and ZCI will produce splinter-free cuts. As part of the routine. saw marks (from the Kapex or SawStop) are removed with a handplane.

 

[AofD]

Okay, I tried a vertical cut using a chop and a pseudo slide cut.  I wasn't able to get a full slide cut due to interference.  Dust collection did well on both cuts as expected.  The start of the slide cut was cleanest.  My conclusion is that the cuts with steepest angle shoot the dust stream directly into the dust collection cavity whereas shallower cuts push the dust stream closer to the exposed edge of the dust boot resulting in higher probability of dust particles not being sucked up.

 

[batmanimal]

Very informative, thank you!

Consistent with what I’ve noticed anecdotally. I’ve taken to calling the single slide cut “the kapex cut” (although your name for it is undoubtedly more descriptive). The kapex cut also involves letting the blade slow to a complete stop before lifting. Agree that DC can be quite good with this technique, especially with the 36mm hose.