Dust Collection Progress..

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Blog entry by CraftsmanCollective posted 09-08-2008 06:52 AM 28804 reads 25 times favorited 16 comments Add to Favorites Watch

So in my first blog entry I touched on my dust collection progress. I’ve recieved a bit of interest with it so I thought I might share some of what I’ve learned to help others get a head start on thier system or to improve the system they already have. I’ve spent a ton of time researching and testing this stuff and can geniunely say that what I post here works exceptionally well. I do alot of work with MDF and we all know of the hazards of wood dust, especially MDF. Im sensitive to it and suffer from allergies in the Spring that literally shut down the shop if I dont medicate, and even then Im super sensitive at that time of year. But I love woodworking, its my business, so for the last year or so I’ve really focused on improving the dust collection of my two biggest offenders, the mitersaw and table saw.

First the miter saw. I’m using a 12” Bosch Slider. Great saw, with good capacity, and up front controls, what it lacked was dust collection so I started trying a few things. First I tried collecting the dust by means of a catch behind the saw, it helped but I couldn’t generate enough airflow behind the saw to catch all the dust. After thinking about it and doing a little research…

check out this great resource: solution was to catch the dust as it came right off the blade by extending the collection shroud.

In the photo above, you can see the shroud extention and the tapered cone reducer, both were considerable improvements. The shroud catches the high speed stream of air and dust as it is thrown off the teeth of the blade. I found this to be far more effective than trying to control the cloud once the dust got a chance to ‘poof’. The tapered cone reducer came about as I struggled to find an adapter that would allow me to adapt the stock D/C snout on the saw to a 2-1/2” hose. What I discovered after finding a readily available adapter was that my tapered adapter allowed for considerably more velocity as the ‘steps’ were minimized on the interior as my adapter slides over the snout but into the hose rather than over it, where commercial adapters are generally female / female, which means the hose slides into the adapter and against the direction of the airflow, creating ‘steps’ on the interior of the transitions that increase air turbulance, thus reducing airflow or CFM. Since I was going through all this trouble to maximize CFM, I also ‘ported’ the interior of the stock Bosch collection shroud to remove casting flaws and open up the ID as much as possible. The photo below shows before.

The photo below shows the port after a little work..

Then I hooked the whole thing up to my biggest shop-vac. Cut the hose to be as short as possible (to increase efficiency) and added a switch that turns the vacuum on when the saw comes on and runs for 7 seconds after tool shut off to clear the hose. I then upgraded the filter to a HEPA filter and added a sheetrock bag. Clean exhaust, filters stay clean, snap to clean. Success..

Heres a link below to a video of the system in action. Notice the sawdust stream being caught off the blade and that there is zero dust on the back of the saw after the cut. I figure Im collecting about 95% or better. This system works so well that even if I disconnect the vac but leave the hose on, the sawdust still comes blasting out of the hose with no vacuum attached.

Feeling quite triumphant with the miter saw, I moved on to the table saw to see what could be done there…

My first attempt was to simply hook up the system as delivered from the manufacture. It didnt take long to realize there was plenty of room for improvement. The stock 4” dust port in the bottom of the cabinet was about as effective as putting a broom in there. Once enough dust piles up inside the cabinet gravity slides it to the port where it sucks up what it can reach. I cant believe this is what is commercially accepted as dust collection.

My first move was to again try to capture the high speed stream right off the blade and found this rather easy since my saw had a shroud to direct the dust to the bottom of the cabinet that worked quite well. I simply attached a 4” hose to that with a few screws.

Now the dust off the blade is being shot right into the hose Heres a top view.

I cut the hose about 4-5” vertically to get it to ‘open up’ a little more, you can see that in the top view. Then I cut a 5” hole in the opposite side of the saw cabinet to route the hose through. I mounted the blast gate right there on the side of the saw, then on to the dust collector stationed right next to the saw which minimized hose length, thus maximizing efficiency. I also deleted the elbow at the dust collector and connected the hose directly, deleting a very ineffiecent 90 bend. I also positioned the jointer right here and attached it as well. Both machines share less that 5’ of 4” ducting, which I found to be significant as the longer the duct run the lower the CFM available from the D/C. Both machines have blast gates to allow each machine to use the full available power of the 1-1/2 HP D/C.

I found that with the directly attached hose, the tablesaw dust collection was vastly improved, but I still had material coming off the top of the blade and needed a way to catch that. I started researching over arm systems and found those readily available to be bulky, cumbersome, and expensive. They also limited the view of the blade which I didn’t like very much. Finally I found the Shark Guard made by a fella named Lee out in Florida at LeeWay Workshop. He hand makes these gems one at a time in his tiny shop. Perfect.

Since it took four weeks to get the Shark Guard, (Lee had to make it you know) I had a little time to think about the overarm set-up. What I came up with was a simple design made of ABS readily available at any hardware store. Total cost of the whole setup including the shark guard, less than $150. Sweet.

Now I had another problem, I had to work a 2-1/2” hose into the system. The only part I could find to adapt a 2-1/2” hose into a 4” system was a cheezy adapter that would require another ‘y’ into the system. Since I wanted to keep the duct system as short as possible, I decided to build my own manifold. First I took a 4” ‘y’ and drilled a 2-1/2” hole at an angle to create another port into the ‘y’.

Then I cut the 2-1/2” end off the 2-1/2” x 4” adapter..

Then I welded them together with ABS cement..


Once dried up the finished manifold was installed.

So now when the D/C comes on Im pulling dust from the blade top and bottom. Works like a champ. Now the two biggest dust spitting offenders are tamed in my shop and I’m quite the happy woodworker. The only problem I have now is that the D/C filter allows too much micro dust to escape. The only solution I see is upgrading to a cyclone system, but that will require a complete redesign of a much larger system. For now, I have at least collected the bulk of it. If I make any significant gains, I’ll be sure to keep you all posted. Feel free to adopt anything you find here, I can only hope that my obsession will inspire others and that my work will save someone else a little time.

If anyone else out there has some good ideas with dust collection, I’d love to hear about them !

-- Robby Myer, Walnut Creek, CA

16 comments so far

View GaryK's profile


10262 posts in 4799 days

#1 posted 09-08-2008 07:53 AM

Some very cool ideas there!

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Schummie's profile


203 posts in 4576 days

#2 posted 09-08-2008 11:57 AM

Hello CRaftsman,

That looks great, the solution with the mitersaw look like the solution you see on the Festool Kapex or not?
Great that you translate this solution to your one mitersaw, you van see on the video that it works great on
your mitersaw.

-- Greetings from the Netherlands.

View Grant Davis's profile

Grant Davis

826 posts in 4719 days

#3 posted 09-08-2008 02:26 PM

Thanks for the post. I am having my garage rewired right now and plan on setting up the DC first and this helps.

-- Grant...."GO BUCKEYES"

View northwoodsman's profile


288 posts in 4557 days

#4 posted 09-08-2008 02:34 PM

I really like your idea for the miter saw dust collection. I have a Dewalt sliding compound miter saw and when I hook my dust collector to it, the suction pulls the rubber “flaps” together providing no dust collection. Now I have a project for next weeekend! I am going to modify my saw using your ideas. Thanks and keep the ideas flowing!!!!

-- NorthWoodsMan

View ND2ELK's profile


13495 posts in 4585 days

#5 posted 09-08-2008 06:34 PM

Really like your miter saw ideas! A few questions if I may.

1. What is the black on the end of the collection shroud?
2. What gauge metal do you recommend using?
3. I presume you made some type of template?
4. A little more info on how the shroud and cone was made?

Any information would be greatly appriciated

-- Mc Bridge Cabinets, Iowa

View CraftsmanCollective's profile


46 posts in 4373 days

#6 posted 09-08-2008 06:51 PM

Thanks Guys! Appreciate the comments.

1. The black extention is just duct tape. I’ve experimented with a few different things (rubber included) and keep going back to duct tape, Its rigid enough, flexible, and cheap. Right now Im working on a setup with brushes that is showing some potential.

2. The metal is aluminum about 18 gauge I guess, its actually a metalmica laminate scrap from another project. It has to be stout enough to hold up under vacuum, but soft enough to form by hand. I think aluminum flashing would work well.

3. Yes I first made several templates from manilla folders until I got a shape I liked.

4. I’m actually writing up a magazine article on this, (lumberjocks get it first!) When I finish it I’ll add it to the blog in the next week or so.

I tried rubber twice for the lower extention, first attempt was inner tube, sucked up under vacuum, second was some rubber sheet from the hardware store, that just wasn’t flexible enough. I kept returning to duct tape.

Yes it is similar to the Kapex design. It just makes sense to capture the dust right off the blade.

-- Robby Myer, Walnut Creek, CA

View PurpLev's profile


8574 posts in 4459 days

#7 posted 09-08-2008 07:31 PM

Nicely done, I’m in the midst of setting up my dust collection ducting and this post was particularly interesting. I noticed you used some ABS PVC which according to research (also Bill Pentz size) has the highest air resistancy inside…. out of curiousity why didnt you use 2729 PVC which is much more effieicnt- lighter in weight, and actually (from what I’ve seen so far) less expensive?

I am planning to use the 2729 PVC myself, but can only find 4” pipings at the local big stores, so I may need to run an order online for the 6” pipes that I am planning to use for this ducting project.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View CraftsmanCollective's profile


46 posts in 4373 days

#8 posted 09-09-2008 08:36 AM

My duct runs are very short and bendy, hardpipe just wouldn’t work for this application. WHen (if) I go to an overhead system I’ll go 6” hardpipe, possibly the PVC but if I go to that extent I’ll probably go formed steel.. the overarm I made from ABS as it was readily available and at the time I was prototyping. Now Im working on a revision made of thinwalled steel (muffler tubing). The ABS does the job though and it was just a couple bucks..

GaryK. Thanks! and congrats on the summer win, amazing inlays… your wifes friends must be super jealous.

-- Robby Myer, Walnut Creek, CA

View Dfish's profile


3 posts in 4264 days

#9 posted 12-11-2008 07:37 PM

I like the shroud setup on your miter saw. I have a 10-inch Bosch and am thinking about doing the same thing. I am assuming the aluminum portion of the shroud is set so it doesn’t hit the normal size stock you cut, and the duct tape section is to provide flexibility when you are cutting tall pieces, like mouldings. Is this correct? You indicate you are thinking about trying brushes. How has this worked out?

View CraftsmanCollective's profile


46 posts in 4373 days

#10 posted 12-12-2008 08:07 PM

Thanks. You are correct. The duct tape allows for a flexible skirt to reach down and catch the material coming off the blade while still being flexible enough to flex over mouldings or collape on top of thicker material. The brushes hit the back burner. I got real busy in the shop lately and the tape works real well so I haven’t experiemented lately, but a recent kickback has bentup the aluminum so I will need to make another. This next one will have the brush setup. I’ll post when I get it done.

-- Robby Myer, Walnut Creek, CA

View Mike Pooley's profile

Mike Pooley

8 posts in 4044 days

#11 posted 07-20-2009 01:51 PM

Hi – I love this , its what i have been looking for, for a long time.
I have the Bosch 10” sliding mitre saw and your idea wont work on mine without cutting away part of the right hand fence.
did you have to do that with yours? and if you did, how much did you cut off and does iit have any disadvantages ?



View CraftsmanCollective's profile


46 posts in 4373 days

#12 posted 07-20-2009 09:17 PM

Mike, The sliding 12” has fence ‘wings’ which slide out of the way of the shroud. If your fence is fixed you may have to modify it some. If you cut a little away it should be too disadvantageous, since you’d only need to take away about an inch or two. I’d recommend leaving about an inch of the fence at the bottom (height)where you do cut some away so that your smaller pieces still have a fence, then set your duct tape ‘skirt’ at that height. I’ve been using this setup for over a year and it is still working great, even though the shroud is getting pretty hammered from the occational kickback. I’m getting the itch to build the next generation. I’ll post up when I do. I’ve also got some really good stuff going for the band saw and the drill press..

-- Robby Myer, Walnut Creek, CA

View a1Jim's profile


118104 posts in 4388 days

#13 posted 07-20-2009 09:25 PM

Good thinking nice innovative thinking


View mmonacella's profile


2 posts in 4015 days

#14 posted 08-18-2009 04:42 AM

Thanks so much for the great post and pics! I’m looking forward to trying this out myself. When you say “Then I hooked the whole thing up to my biggest shop-vac”, what by chance are the specs on it? What’s the rated amps or CFM on it? I’m really considering doing this modification but I also want to make sure the suction is even in the ballpark before getting my hopes up.


View John Gray's profile

John Gray

2370 posts in 4696 days

#15 posted 08-26-2009 01:55 AM

“This next one will have the brush setup. I’ll post when I get it done.” What happened to the brush follow up?
I’ve watched your blog since it started and now I need to setup my Bosch 10” on the new miter saw cabinet that I’m building from Wood Magazine. They recommend/ use a hole under the saw for collection but I can’t see that working at all.
Link to the Mitersaw Center:

-- Only the Shadow knows....................

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