Meant to post last night.
Well took a look and here is what I found.
Looks like there is not enough draw on the dust collector and the saw dust sits on the slide.
So still need to keep an eye on it until we get a frictionless slide…
Did you find the rest of my finger in there?
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Could we extend the hose about halfway into the saw. It looks like it must take a pretty tall pile at the front of the saw to be steep enough for the sawdust to fall towards the exhaust port. Or put vent holes in the door so there is enough airflow to float the sawdust in an airstream towards the exhaust port.
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For what it’s worth, some of the videos and websites I’ve seen about “tuning” dust collection on table saws talk about the notion that it’s not always the collection hose/suction end that needs “tuned”, but the inlets; where they are, and what their flow volume is can make huge differences (I’m told; no practical experience on this personally).
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We could make a clear plastic door with holes along the bottom and a sliding piece that partially covers the holes
Use the table saw for a few weeks, slowly block off the vent holes in small steps, when we starting seeing sawdust collect in the bottom it means there is not enough air flow across the bottom of the black plastic thing to stir up the sawdust enough to get it to the exhaust port, open up the vents a little, try it for another few weeks. Decide if we want to keep the clear door or modify the OEM door or determine this was an interesting experiment but a waste of time and didn’t work as imagined.
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Or…As long as the sawdust doesn’t build up high enough to get into the belts or blade don’t worry about it. It would effectively form the ideal conical shape that exhausts anything added any higher to the pile.
If the sawdust builds up enough to block the exhaust port it probably means the vacuum lines are plugged up or restricted and not getting the air velocity needed to pull the sawdust out of the machine.
I think it would be better to see if we have a problem by pulling the hose off the back of the machine rather than opening the door that is as far away from the port as you can get where we would expect to find sawdust.
Right…effective dust control is not about suction power but about proper flow and CFM.
I was going to ask about conducting an experiment: clean out all dust, then see if leaving that door or port or whatever it is in the original picture open creates a way for hose in back to get a better draw from the front; any dust falling down from top would be carried away in that airstream…maybe.
Or, @rlisbona’s point is a good one: the goal is not really to have a pristine cabinet interior, just to achieve a steady-state where no incremental dust builds up and creates a clog or hinders saw performance.
I couldn’t tell how much was sitting back at the outlet but one of the things that will need to be addressed is the insert was collapsed due to the weight of the dust. It popped right back into place once cleared.
Any solution would need to address this as I think the volume of the cabinet is such it is going to be very difficult to keep clear. The velocity needed to keep larger particles suspended or moving to the outlet is not there. So any appreciable build up will pop the ramp out of place again.
Would it be possible to extend a hose or pipe into the cabinet with a slot or slots along the bottom and sides? If we can draw all along the ramp inside the cabinet it could get the dust at the point where it is collecting.
After sleeping on this, I don’t like my idea of letting the sawdust build up, there will be long thin wood strips mixed in and those would stabilize the dust pile so the angle of repose (angle where the dust pile naturally collapses) could get very steep and eventually plug the outlet and build high enough to interfer with the moving parts.
So air vents to keep the dust suspended till its sucked out seems better and we really don’t want those long strips and chunks sucked into the exhaust port and piping so I’m wondering if the exhaust port should be higher up rather than on the bottom. Seems like when you take the door off you would just want to find strips and chunks too big to get through the vacuum pipes and very little sawdust.
Please discuss.
Might have better luck trying to fluidize the debris than to get enough velocity in that large housing. It appears you have a chute trying to guide the debris to the vac port. And it appears the chute might be a tad flimsy since it sags with the weight. So, being the crafty makers you are, make or 3D print a similar shape that has two layers with a gap between the top & bottom and sealed along the edges. Perforate the top layer and then cover with a porous membrane that will allow air flow, but not let sawdust through. Wire in a small blower that starts when the saw starts and is piped to send enough air into the chute inner section so it will fluidize the debris just enough to make it flow to the port. (Not unlike the fluidizing systems used on 18 wheelers that haul finely ground powders.)
You could do the same thing with compressed air and a solenoid, but I would not recommend that unless you have a foolproof way to never overpressure the “chute”. And fools are so darned clever at beating safety systems …
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I think keeping the dust free flowing is key, but I do not think using compressed air is the solution as the holes will eventually fill and block. Better would be some sort of vibration plate to keep the dust moving down toward the outlet.
That’s a worthy suggestion.
Which would be a design problem because the specification of “membrane that will allow air flow, but not let sawdust through” wasn’t met.
One simple option would be to have an open tube or set of tubes that pulse air into the debris zone on a cycle (10, 15 secs?) to break up clumps and “sweep” the debris toward the exit port. Some runs of 3/8-1/2" tubing set above the pile zone & angled to move material toward the exit should be large enough to keep from clogging if positioned adequately.
Sawmill creek has a thread in this very problem:,.
https://sawmillcreek.org/showthread.php?216716-Powermatic-66-Dust-collection-Improvements
Basically they increased the dust port size from 4” to 6”. And they building a better air box that incases the motor… from what it sounds like a router motor dust box… the new skillsaw has a dust guard around the blade to channel the dust this might be a better solution…
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I this video they increase the port size to 6” and ramped the dust to the port and closes off as many hose as they could to increase air velocity at blade as well as adding above the blade dust collection
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I have the same challenge getting debris out of my Delta 33-L552 Unisaw. A few weeks ago I hooked up an idle blower as an experiment. It is a HF unit like this: https://www.harborfreight.com/13-gallon-industrial-portable-dust-collector-31810.html?_br_psugg_q=dust+collector
Since this blower was designed with the intent of moving dirty air, I connected the blower suction to the saw exit port and moved the collection system hose to the blower discharge, My hope was that the extra umph this blower provides would increase the flow through the housing, and hopefully keep the housing interior inventory under control.
It has been in operation like this for a few weeks. Today I cut a significant amount of Eastern Red Cedar and decided to peak down into the cavity to see how it was working. This saw is not unlike the SawStop with a separate housing near the blade emptied by hose that ends near the cabinet exit port. Frequently the hose would plug up and the housing would build a significant debris inventory.
When inspected today, the blade compartment was empty
and the cabinet had a clear bottom with an “angle of repose” related pile in the corners. This was far better than it would be without the extra blower.
So in my case extra flow was all I needed to essentially end the “housing debris inventory problem”.
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This might another issue to the dust build in the system… everything I’ve read suggests that each Table saw needs us own run to the main collection pipe… t- off like that takes away from performance… .
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Honestly I think what we have in place now might work once we get the new filters in, cause even freshly cleaned the filters are so far beyond manufactures recommendations the amount of cf of flow through we’re getting isn’t close to optimal ,were essentially 15k miles into an oil change, that and will a few minor seam repairs i feel it might work just cause that many cfm should stir a majority of it up before settling
Chris, the powermatic has always had an issue with dust removal… when both saws are in use, blast gates Open it’s reduces vacuum to both machines… the current setup is an either or not really meant for both machines to use at the same time… while it might work, it clearly not working very well…
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No I agree, but that’s unfortunately an un realistically fixable issue cause it’d be stupid to redo the ducting just to have it be rendered useless when we go to rip it all down once the move starts, so that’ll be fixed once the move happens and I’d imagine a thorough planning in combination with the w auto blast gates installed will keep us from running into downfalls such as the splits in ducting we have now.