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: http://billpentz.com/Woodworking/Cyclone/Index.cfm
....my 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