Table Saw Dust Collection Mods

[bitingmidge]

Tried this on the machinery connection thread (which did get a bit off track in the end!!)

So back to dust collecting,

I have just built a 30mm high spacer for my 10" Contractor's Saw (Jet) to raise the table height to a more meaningful height!

It's just a square of timber which fits between the saw frame and the stand, but in doing so, the whole dust connection thing came into focus.

Before connection, the dust outlet is in the bottom of the frame, 320mm below the table. Being a typical contractors saw, the whole of the back face is open, and it's pretty clear that the only sawdust that actually gets sucked up is the stuff that falls into the DC connection hole.

I am thinking of raising the bottom so that it is much closer to the retracted saw (250mm below the table) and filling in the greater part of the back opening. There is still plenty of airflow...certainly more than the diameter of the duct.

What thoughts please??

How do the saws with fully enclosed bases fare, any better, or do they also end up with a pile of sawdust surrounding the outlet?

Cheers,

P

[Bruce Micheal]

Midge
I have a Carbatec 10" saw (CT-250). The bottom of the saw blade under the table is enclosed in a plastic shroud which has the DC. This shroud is conected to the saw itself so it moves up, down and sideways with the saw when raising, lowering or tilting the saw. At least 60% of dust fills the shroud and the other 40% flys off the top of the blade above the table. In my case fitting an extra DC to the saw guard would solve all dust problems.
:)

[silentC]

My cabinet saw has a sloping floor that directs the dust that falls inside towards the dust port. Haven't got a dust collector attached to it yet but the dust tends to fall out of the port and onto the floor, which I suppose is a good sign.

[Wayne Davy]

Midge,

With my KS-12K which is a Contractor style, I have done the following to improve the Dust Collection:

1. Sealed up the gaps under the table between the cabinet with some grey foam strips (concrete expansion foam I think)
2. Used one of the rare earth magnets and cut a piece of sheet metal to cover the hole where the Height Adjustment wheel is. Using the magnet, I can reposition it when tilting the blade.
3. To seal up the back before the Motor, I have made up a 'Boot' type arrangement. To do this, I used one of the Dust Collection Bags from the 2hp D/C I based the Cyclone on. I cut it down to about half the length so that I ended up with a big 'tube' of fabric. Then I fitted it over the motor and onto the Motor mount and fixed one open end over the whole back of the Saw. The other open end I have closed up with some clothes pegs at the moment but I intend to use some elastic for a more permanent method. (This will only work if you have a belt guard in place btw)

These mod's have improved the dust collection immensely. One thing though, I only sealed up the front Wheel hole as I have the overhead guard connected to the D/C. If I didnt, I would leave the front cabinet hole open so as to maintain the Air Flow especially if a zero clearance blade insert is used.

There you go, clear as mud ;)

Hope this helps.

Cheers,

p.s. Cannot wait to see some pic's of all the plumbing.

[jacko]

I found that the flexible magnetic material that they use to make signs for cars, etc. is great for closing up those holes. Easily removable or moved when other settings of the saw are required. Got some off-cuts from the local magnetic sign supplier, almost for nothing (seem to remember something about a slab of beer next time-----)
jacko

[derekcohen]

P

My 12" Carba-tec contractor saw is sealed up at the sides similar to Wayne's. The whole lot is sealed at the bottom as well and I have also attached a gate for a vacuum. Having done all this, I rarely bother to use dust extraction at that point. Yes, the tray inside fills with sawdust and requires emptying out every now-and-then (more then than now), but my experience is that there is more dust flying around at the top of the saw blade than at the bottom.

My tablesaw, probably like most, is set up with s close-fitting plate around the blade. Only a small percentage of the dust is driven down, more goes up and outwards. So I believe that dust extraction it is likely to be more efficient is from the blade guard. My plan is to build a new guard that can incorporate dust extraction.

Regards from Perth

Derek

[soundman]

Improving the airflow into my overhead guard was certainly worth while.
It now has two 3" hoses fed from a 4" rigid pipe.
Quite a bit of stuff is thrown off the back and out the side of the blade.
There are times now when I have the guard good & low where chips can be seen to be heading out the front only to do a U turn & go up the spout.
Most of the stuff that ends up below the deck was going to go that way anyway. If you can get the pick up close to the front bottom of the blade you will pick up more.

My machine is fully enclosed (with improvements) and I still have to shovel out the bottom from time to time.

[bitingmidge]

Work on the saw and the DC system stopped for a bit while I did the canoe prototype and finished off a rough set of 9' oars :eek: :D :D.

Thanks for all the replies... I sort of got to a spot somewhere between Wayne and Jacko I think...

I plan to do a number of things: reduce the volume of the "box" under the blade, seal as much of the back and the front as possible using a combination of magnetic strips and timber...

Will report back in the future.

Thanks again,

P

[bitingmidge]

OK - as promised!!

I got to the part in the mediocre workbench where I really needed to fire up the TS. Which led me to think about how much mess that was going to make and how I really should finish the dust collection mods.

Never being one to let completing a project get in the way of starting another one :D here's where I got to:-

Photo 1
Before taking this shot, I cleaned all dust out, and ran about ten metres of 12mm melamine faced board through the saw, connected via the standard outlet to a Jet DC1200 through 3 metres of 100mm flex.

Note the timber spacer that I have installed to bring the table to a more comfortable height for me (finished with red and black insulation tape on the outside to make it look more "Jet").

Also note the little crater in the far corner where the build up of sawdust has fallen through a gap in the metal onto the floor!

With more use dust builds up all the way around the outlet, and seems to be removed more or less through gravity! I think that no more than 70% of dust goes to the collector with the stock setup.

Photo 2
A pretty clear illustration of how much dust falls outside, again clean before the test cuts, and pretty much indicative of how the floor looks at the "front" of the saw after a session.

Photo 3
New cowl mock-up. Designed to reduce the volume collected around the blade as far as possible, with the outlet directly under the leading edge of the blade. (I chickened out and positioned it a little forward of centre in the end, but have enough room to move it forward later if I feel it needs it).

Photo 4
I installed the cowl (bugger of a job really;) ) basically assembled it inside the machine without dismantling anything..(.it was supposed to be a prototype, but will probably be the finished thing now!!) and repeated the test in photo 1. SPECTACULAR DIFFERENCE!!

This is with the back of the saw (round the motor) completely open. I can hardly wait till I've built some sort of enclosure similar to Waynes' (thanks for the info Wayne BTW!) Note there is a little dust round the aft end, and it would certainly be more of a problem with a bigger job, but we are probably collecting close to 95% or more now.

Photo 5
I used a couple of old fridge magnets to cover the hole round the control wheel in the front of the cabinet.


Now that the thing is pretty "clean", it is obvious that I'm going to have to seal under the top with foam (again thanks Wayne!), and I will either box in the motor eventually or build a fabric enclosure.

I haven't got any collection setup yet for the blade guard, but the above set up also reduced dust above the table by a huge amount (at least half- maybe more. If I was a scientist I would have weighed both samples!)

Hope this is all of some interest!

Cheers,

P (who has one project NEARLY finished now!)
:D :D :D

[echnidna]

wouldn't it have been easier just to use spacers to lift the complete saw up higher instead of just the table?

[bitingmidge]

wouldn't it have been easier just to use spacers to lift the complete saw up higher instead of just the table?
Bob,

The spacer is between the saw body and the stand, and the stand also is on a mobile base.

The original dust collection base was bolted to the stand rather than the saw base, and while it would have been easy enough to build a new "bottom", the DC outlet was originally so far away that it really only collected whatever fell into it rather than sucking it away (and my last contractors' saw was worse!). I then got to thinking about Pill Penz's stuff, and figured if the big bits of dust weren't getting sucked down, the small bits probably weren't either!

I was happy enough with the standard setup until I moved into the new place with the glossy floor and it became more obvious how much dust is escaping. At the moment I am going through this "surgically clean" phase, which is not really in keeping with the untidy inner me, indulge me for a bit, and I'm sure it'll pass!!

Anyways, for a few hours mucking around I am quite surprised at the improvement, and would recommend it to others. Now I'm spurred on to do bigger and better things with all the machinery in the shed! Currently more into tinkering that actually "doing" anything!

Cheers,

P

[bitingmidge]

Never let a thread die I say!!

Now that I'm using the Grr-rippers, the overhead dust collection gets a bit trickier, because for any ripping work at all I need to get my hands and the Grr-rippers over the blade.

I am thinking of using the original plastic hood, and through the use of a bit of heat, (and other cleverness) attaching it to a 4" pipe, but this will be mounted at leat 300 or more off the table in the ripping position.

Would anyone who has a working DC on an overhead guard care to make a guess as to whether this is worth doing at all?

I am inclined to think that any pickup is better than no pickup!

Cheers,

P :D

[journeyman Mick]

Midge,
I run a 2hp dc with one 100mm line to the port on the base of the saw and a90mm line to the overhead guard. The guard was 65mm and next to useless, now that it's 90mm it's one step removed from next to useless :D . Because the port on most guards is at the back of the guard they will only pick up what is coming up with the back of the blade. In the case of my saw (CT 250TS) which has a shroud surrounding the blade entirely below the table, very little comes up the back of the blade.

The dust that ends up on top of the table is the stuff that's shooting forward over the top of the workpiece. This is fairly minimal as it's just what the back teeth are removing from the kerf. I believe that a port more towards the front of the guard might work better, especially if connected to a vac rather than a DC (higher velocity, so more likely to suck up particles from a distance. I doubt I'll muck around trying to get it any better though, lot's of better things to do. Just try hanging your DC hose about 300mm of the table to see how much it will pick up, I'm guessing next to nothing.

Mick

[Wayne Davy]

Midge,

I doubt it would be worth while. I find mine with the 4" connection has to be quite close to pickup the bits coming out. Reason is that the chips/dust has velocity and you need to pick up close to grab it otherwise it spreads out side the range of the hood.

Probably just better to forgot the top hood and max the air flow in the cabinet.

[Wayne Davy]

Mick just beat me. But same conclusion. As to the ports at the back, I agree. That is why mine is forward (about 1/4 back from the front of the blade) and 4" pipe. However, even that does not work for all cuts particularly using a sled on the table. The dust just goes out the side - not much though as most ends up in the cabinet to bottom pickup.

[Harry72]

He he he, "Grr-rippers over the blade" you need to connect some 4" duct to your shirt sleeve!

Would it be possible to mount a slot/rectangle shaped duct on top of the saw fence level with the front of the blade too create a cross draughting effect?
See the quik made up pic:D

[soundman]

I have 2 x 3" ports on my overhead guard and the results are quite good if you keep the guard reasonably close to the work.
If I'm edge trimming I block off one side of the guard with a block to improve air flow.
I run a sled quite a lot but mine onlyruns on the left side of the blade & the fence is cut down near the blade top allow the overhead guard to work as a guard.
I'm not keen on sleds made the way most of the us mags show because you have to remove your guard to use them. Not acceptable.

I have had the idea of fitting a couple of lengths of brush to the sides of the guard to help with the suction.

I had a major improvement replacing the most flexible duct with 4" pipe on my overhead the only flex is the two sections of 3 " about 450 long that go down to the guard.

I have managed a substantial reduction in dust "spray" from the top of the saw.

cheers

[bitingmidge]

Harry,

Good thought on the fence mounted pickup, but sometimes the fence is a long way from the blade!

I have thought about a pickup in the back of my shirt and wearing long sleeves with open cuffs though!

:D :D :D

P

[vsquizz]

I don't understand Midge...I mean I've looked and studied..and come to the conclusion...YOUR SHED SUCKS!:D so the thing should extract really well;)

Cheers (oneday..just oneday...I'm gunna..)

[Rusty]

No, this is going somewhere! I reckon 1' flexible duct velcro strapped to your leading arm with the intake at the wrist...saves changing hoses as you change tools. How can I wire myself up for 240v, to save walking to the power point?

Come on, it's good...

Just not for table saws. Or any type of static machinery. But you get it.

[Harry72]

I was modding the POS Tsaw of mine the other day to accept a connection from my new DC(originaly was 28mm now 102mm!)and I gots to thinkin about this problem of dust above the table, obivously some of the saw dust is trapped in the teeth of the blade as it rotates and when it hits the exposed blade area above the table it "flings off" so we need to draught the blade guard.

What if we could rid the of this dust before it gets to the top, I was thinking of blasting compressed air 90° across the teeth inside the cabinet so it can be draughted off by the DC in the normal manner.
This may even get rid of the need to draught the top guard and allow for use of jigs/Grr Rippers etc without making a mess?
Add it would also serve to cool the blade while doing long ripping cuts.

Has anyone heard of this before, or even tried it... ideas, comments?

[rev]

What if we could rid the of this dust before it gets to the top, I was thinking of blasting compressed air 90° across the teeth inside the cabinet so it can be draughted off by the DC in the normal manner.
This may even get rid of the need to draught the top guard and allow for use of jigs/Grr Rippers etc without making a mess?

Interesting idea!

Maybe you could achieve the same result "passively" by using the suction from the DC to provide the airflow past the blade perpendicular to the teeth. You could put in a short piece of duct vented outside of the saw cabinet and ending at the teeth of the blade. seal up the cabinet so that all the airflow of the DC is drawn across the blade to clear the gullets of any trapped sawdust that might otherwise be flung out the top. The dust laden air is then sucked out of the cabinet at the normal dust port.

[Harry72]

Yeah that might work, but I think with the compressed air it will be concertated to a very small area with much pressure, a DC wont create this kind of vacuum in such a small space to get the same pressure as comp'air would genarate.

Maybe an actual vacuum cleaner might do it tho? It would have to be very close to the blade to work, which would be a bit of a clearance problem with a tilting arbor.

With comp'air it would only need a small 3-6mm metal tube that could have a 90° bend near the blade. Possibly use automotive brake line tube.

[soundman]

The ideas of compressed air are all very interesting but it only deals with one of the many sources of above bench dust.

The majority of the dust will be forced down below the bench & thrust downward. Yes "some" will come arround & out the top. That will be joined by the exit wound dust from the blades second path (upward) thru the board.
In the case of edge trimming there will be a larde amount of balistic dust thrown away from the blade that isn't confined by the kerf.

The bigest reduction in above table dust I have found is dust extraction in the blade guard.
My current arrangement is a bruit force High airflow method, My old saw I just put a 32mm hole saw thru the top of the standard guard & glued in a piece of 32mm conduit onto which I hooked a standard vac.
This mod would work for most US style blade guards. Because the guard rides the work the capture is very good.
Its cheap & easy.
cheers

[Harry72]

I get what you mean by edge trimming, but the idea is to rid dust while the guard is removed for cutting tennons and using stuff like the Grr Ripper system, so the blades kerf that contains the dust is enclosed by the wood being cut and the guard cant be used.
I noticed with my POS TS the only dust emitted is from the blade as it comes back through the wood, like you said.
If the dust was removed from the blade below the top and before it returns to the top surface, Im pretty sure there will be minimal dust in the guard in the 1st place... but we wont really know until its tested!
May give it a try tomorrow, see what happens.

[Harry72]

Ok I did some experimenting today, grabed some S'steel 10mm tube to use as a air nozzle and made my blower gun fit into it(bit of a file).
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/airin.jpg

First I put the air outlet at the front of the blade, it worked ok but still seemed to get some dust above the table and it tended to blow the dust out from the bottom of the front part of the saw(see full view photo's for some foam jammed in to stop this, this saw was never designed to take any draughting). Then I placed the air outlet at the rear of the blade about 5mm from the blades teeth and approx 2cm's down from the table top.
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/airout.jpg

This worked very well! The next two photos are the saw cleaned off with a vacuum cleaner before any cutting.(all photos are of the saw/floor cleaned with vac before cutting!)
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/cleansaw.jpg
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/cleansaw2.jpg

The next two photos are after cutting about a meters worth of wood with the air run at 30psi, I tried running it at a higher pressure 60psi but it didnt seem to make any differance.
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/afterair.jpg
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/afterair2.jpg

Just for comparision I did a cut of only 150mm in length without any air(dusty still running)
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/withoutair.jpg
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/withoutair2.jpg

So going by my results the air blowing across the blades teeth at 90° seems to remove a very good percentage of the dust from the blades kerf/teeth, obivously if the guard is fitted it we would get better results... but thats not the point of this.
The idea is to remove the dust while using a table saw with no guard attached, ie while cutting tennons or using a system like the GrrRipper's or even cutting down the height of a box shape frame.

A few suggestions that I can think of,
1. A small duct opposing the airoutlet, directing the airflow/dust downwards towards the DC outlet of the saw casing/base might help. The air pushes the dust in one direction if this is towards a gap in the saw's outer casing it will escape through it.
2. 30psi seems to be enough with a air tube of 7.5mm internal dia, going higher only works your compressor hard.
3. The air feed tube could be made to hang off the riving knife mount so it moves with the blade as the cutting height/tilt is adjusted, or some sort of bracket to a part that moves with the blade arbor assembly.
4. A flexable joint would be needed to allow adjustment/movement of arbor assembly.
5. If your a tricky cluey type you could rig up a solenoid to shut and open a air valve with the saws main start/stop switch, the rest of us could fit a manual valve on the saw.


Oh and heres me new dusty!
http://img.photobucket.com/albums/v725/ST170ish/woodwork/table%20saw%20experiment/mydusty.jpg
Only got 100mm pvc running to this saw ATM, my new saw(TSC10HB) should arrive in a few days... plus if I cut any more from the back of this cheap POS table saw there wont be any metal left and it would probably implode with this dusty sucking on it!

[bitingmidge]

What can anyone say??? :eek:

Well done!! Even with the photos I'm still sceptical though! :D :D

I think I'll go and have a Bex and a good lie down......

Cheers,

P :D

[rev]

:cool: :cool: :cool: (Really cool!)