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Dan Forman
03-29-2005, 6:58 PM
I have been studying up on dust collection systems, learned lots. According to Bill Pentz's site, one should enlarge all existing 4" ports in our machines to at least 5", if we are to capture the really fine dust which is most damaging. Apparently even a short neckdown to 4" will kill the airflow to the point that the fine dust will not be captured. Has anyone here actually modified their machines to expand the dust port to 5"?

Terry Hatfield
03-29-2005, 10:27 PM
Dan,

I have modified quite a few of my machines to 6" ports using mostly readily available and cheap HVAC fittings. It does make a tremendous difference in the performance.

There are lots of pics and such on my site in the "Shop Tour" if you would like to check it out.

Terry

Jeff Sudmeier
03-30-2005, 8:01 AM
The neck down does cause a big drop in air flow, so if you are running 6 inch ducts, it is best to have a 6 inch port on whatever you are collecting from. If you are able to upgrade all of them, you will get better performance.

Steven Wilson
03-30-2005, 11:03 AM
This is one area where I disagree somewhat with Bill Pentz. You don't need 800 CFM to every tool. Some of the smaller tools are effectively evacuated with smaller DC ports. For example a 4" DC port is appropriate for a 6" jointer and would be for an 8" jointer if it didn't clog on chips so much (5" or 6" port not so much for dust but to keep from gloging with larger chips). IMNO the 12" lunch box planers are reasonably served by a 4" DC port although a 5" port would be handy. Port size depends on the machine.

Bill Arnold
03-30-2005, 11:18 AM
I have been studying up on dust collection systems, learned lots. According to Bill Pentz's site, one should enlarge all existing 4" ports in our machines to at least 5", if we are to capture the really fine dust which is most damaging. ...
I've read through a lot of the data on Bill's site and can't disagree with most of it. But, when a vendor preaches a 'doomsday' message, then tries to sell something, I look elsewhere.

I get decent dust/chip collection on my equipment with the 4" ports built into them. Would a 5" or 6" port be better for my tablesaw? Maybe, but the major issue with my tablesaw is that I don't have top collection and haven't decided how to approach it since I have a router in the extension.

Regards,

Bill Lewis
03-30-2005, 2:05 PM
Almost all of my ports are 5". After the gate, I use 5" flex hose then reduce down at the machine with a 5x4 HVAC reducer. It absolutely works just fine with my DW733 planer. The PM 54A jointer is also reduced this way. It has some spillage, but I think there are other issues, like an open bottom base cabinet, that need to be addressed first. Ultimately I may upsize to a 5", but not after fixing the leaks first. I have even reduced the 5" to 2.5" for the CMS, then reducing the 2.5" to 1.5" at the saw. It works with at least 80-90% efficiency.
So I'd have to say that, in general, the reduction at the machine is probably not as much of an issue as with the size of the DC pipe leading up to it.

eugeniusz luzar
07-13-2015, 4:19 AM
I have been studying up on dust collector (http://www.grupa-wolff.com/dedusting/dust-extraction-systems/)systems, learned lots. According to Bill Pentz's site, one should enlarge all existing 4" ports in our machines to at least 5", if we are to capture the really fine dust which is most damaging. Apparently even a short neckdown to 4" will kill the airflow to the point that the fine dust will not be captured. Has anyone here actually modified their machines to expand the dust port to 5"?


My first accessory mistake was buying a transition that mated my 4" dust collection hoses to the tiny 1.25" port on my band saw. So little air was moved I went back to using my powerful shop vacuum on all tools with small ports. I also bought the 5" replacement port for my band saw lower port.

Mike Chalmers
07-13-2015, 5:09 AM
If 6" ports were so essential, why do most machines come with 5" or smaller, mostly 4"? Why do most machines seen on woodworking shows have 5" or smaller? I am not saying that 6" openings would not be better, I do not have the data to support such a position, however, we can't all afford a purist approach. Nor, in my opinion, is such an approach necessary for most people.

Robert Engel
07-13-2015, 6:02 AM
What are the big dust producers? TS, BS, DS. That's where it matters.
The only one I could possibly change to 6" ports is the DS.
Very difficult on the BS and TS I would have to cut new holes somewhere.

Planers and jointers produce shavings almost entirely don't worry about them.

Bottom line I don't think it will make a noticeable diff.

I still use a respirator messing with Chinese ply or MDF.

Rod Sheridan
07-13-2015, 6:55 AM
If 6" ports were so essential, why do most machines come with 5" or smaller, mostly 4"? Why do most machines seen on woodworking shows have 5" or smaller? I am not saying that 6" openings would not be better, I do not have the data to support such a position, however, we can't all afford a purist approach. Nor, in my opinion, is such an approach necessary for most people.

Hi Mike, it's because the manufacturers don't have to meet a standard for dust collection performance in NA.

Buy a Euro machine and you'll find that the ports start at 120mm, and the machines come with a performance statement as to how much dust they emit at rated airflow. The airflow is also specified in the equipment manual.

In addition, they're designed for dust collection, for example the saw will have a shroud below the blade, and there will collection above the blade.

Regards, Rod.

Phil Thien
07-13-2015, 9:30 AM
Hi Mike, it's because the manufacturers don't have to meet a standard for dust collection performance in NA.

Buy a Euro machine and you'll find that the ports start at 120mm, and the machines come with a performance statement as to how much dust they emit at rated airflow. The airflow is also specified in the equipment manual.

In addition, they're designed for dust collection, for example the saw will have a shroud below the blade, and there will collection above the blade.

Regards, Rod.

What does the statement for your machine indicate it emits for the various functions?

Jim Andrew
07-13-2015, 9:56 AM
It seems to vary by machine. My 15" Grizzly planer works fine with a 4" port. I planned to change it, but it works so well see no need. My G9983 widebelt had a 5" opening, and saw dust on the belt falling off on the discharge side of the sander. Looked at the port, and it had a round pipe welded onto a flat plate on top of a 5" square. So I cut the round pipe off, and made a 5" square to 6" round adapter. Less saw dust now. If I had a bigger dust collector, could cut down on that. Planning to make a under table port for my mm16. Already has a 4", so another 4" would work just fine. When I got my K3 Hammer tablesaw, was surprised to find the guard had a 2" port. Hooked it up, and it works fine for over the blade dust collection. The cabinet is just 4", and it seems fine as well, except when several thin strips plug it up. Hard to get the strips out of that 4" flex hose.

Rod Sheridan
07-13-2015, 10:50 AM
What does the statement for your machine indicate it emits for the various functions?

Hi Phil, I'm working in Virginia this week, I'll send you the info next week.

If I remember correctly it was X number of milligrams per hour during a standard test.................Rod.

Phil Thien
07-13-2015, 10:52 AM
Hi Phil, I'm working in Virginia this week, I'll send you the info next week.

If I remember correctly it was X number of milligrams per hour during a standard test.................Rod.

That would be interesting to see, thanks Rod!

James Gunning
07-13-2015, 12:02 PM
Based on the difference I saw in collection with my machines, upsizing the ports is the way to go. Admittedly, on some smaller machines such as ROS, hand held routers, biscuit joiners, etc. even a 4" hose wouldn't be practical, let alone larger. Those tools are better served by a good shop vac, and if you don't want to clean filters all the time, put a small cyclone in line with the vac. For the larger machines, upsizing the ports will make a big difference. Here is a thread where I showed the modifications I made to my machines to adapt them to 6" hose. http://www.sawmillcreek.org/showthread.php?230820-Yet-another-dust-collection-thread-Adapting-the-machines-to-use-6-quot-pipe Making the changes wasn't difficult, and in my case no major surgery was required on the machines, but WMMV. In addition to the larger ports, I used sealing and baffles in a few places to help direct the chips and dust to the pickup points.

I think the point that is missed concerning the Bill Pentz findings is about ensuring that your machines are not blowing out the small particles that could possibly endanger your health. The whole idea is to maximize the airflow so the very small particles we can't even see are being captured. I don't know why the manufacturers settled on 4" ports. Probably, because years ago that was considered adequate to collect the chips, and health concerns weren't on the radar. It became the de-facto standard in the US and using something larger would possibly hurt sales since most folks were already equipped with 4' piping. In general, the European view is that health and safety are paramount, and doing what is necessary to safeguard that is something the manufacturers had to do. A major case in point would be their use of riving knives long before they were required in the US.

The number Bill Pentz arrived at that was adequate to collect the harmful dust was 800 CFM at the machine. It's physically not possible to get that much airflow through a 4" pipe without a massive blower that would be impractical for nearly all of us. However, the Clearvue, Oneida, Penn State and other cyclones plus many large single stage DC's can move that much through a 6" pipe.

There is a difference between what seems to work adequately (chip collection) and what you can't see escaping (very fine dust-that carries a real health risk).

Wade Lippman
07-13-2015, 12:11 PM
What are the big dust producers? TS, BS, DS.

I expect this will be a Duh moment, but what is a DS? Drum sander?

James Gunning
07-13-2015, 12:20 PM
TS-tablesaw BS-bandsaw DS-drum sander.

Anthony Whitesell
07-13-2015, 12:26 PM
I have fallen into the same trap. If 4" is so widely available, then it must be right. Right? Personally, I believe it is the most cost effective to manufacture so that is what they make. Purchasing a DC with a 4" was a big mistake. I have all of my tools with 4" ports, some dual 4" ports. If you came to my shop, you could not say that a 4" port on the DC or the tool was sufficient.

This is how my review would read of the 4" ports on my equipment and DC.
Bandsaw - not enough collection; much sawdust left in the lower cabinet and falling from the upper.
Tablesaw - not enough collection; mush sawdust flying off the blade at me
Router table - not enough, too many chips in the cabinet, not enough to run both the fence and cabinet at the same time.
8" jointer - not enough, too many chips not collected in the chute but ejected at the end of the cut, chute does not clog
12 1/2" planer - not enough, too many chips ejected from the loading side and/or stuck to the rollers.

16" drum sander - possibly (50/50 maybe better) enough. No dust in on the boards when exiting, I don't see or smell anything when using the machine. Would better/more collection improve removal from the sandpaper? I don't know.

If the DC can't pick up 99% of the chips, it isn't doing a very good job. The is 1 1/2HP top/bottom cloth bag DC with only a 4" inlet and I move it from machine to machine. Before I knew better I spent $$$ on the 4" fittings and made it stationary. More convenient with little (negative) effect on performance.

I have an older Oneida cycle I am working to assemble which has a 7" inlet. I plan to enlarge the ports on the tablesaw, jointer, and planer to at least 5". For the bandsaw and router table, I will re-plumb them so each port is connected to a larger drop or to the trunck directly.

David Nelson1
07-13-2015, 1:45 PM
That would be interesting to see, thanks Rod!

I'll help Rod out317260

Phil Thien
07-13-2015, 1:54 PM
Thank you David but I'm kind of curious whether they provide emissions data which says how much dust escapes. That just seems to indicate the amount of DC needed, not what can be expected to be missed with that amount of airflow.

David Nelson1
07-13-2015, 5:31 PM
Didn't see anything like that. I can tell you that after a good round of jointing I have a very nice pile of chips sitting on the planer bedmaybe about 3-4 scooping hand fulls but the fines seem to be ok. I have to get a new power cord for the Dylos. It got snagged on something and is quit frayed. Might be able to solder it back together but..........any way I'll shut up now LOL

Allan Speers
07-13-2015, 5:57 PM
What about a bandsaw with TWO 4" ports?

If these immediately feed a 2 in / 1 out "Y" fiting, which has a 6" outlet, is this still limiting the dust?

Phil Thien
07-13-2015, 6:01 PM
Didn't see anything like that. I can tell you that after a good round of jointing I have a very nice pile of chips sitting on the planer bedmaybe about 3-4 scooping hand fulls but the fines seem to be ok. I have to get a new power cord for the Dylos. It got snagged on something and is quit frayed. Might be able to solder it back together but..........any way I'll shut up now LOL

Don't shut up? What kind of DC are you using on the Hammer?

Mike Chalmers
07-13-2015, 6:15 PM
My comparison notes below.


I have fallen into the same trap. If 4" is so widely available, then it must be right. Right? Personally, I believe it is the most cost effective to manufacture so that is what they make. Purchasing a DC with a 4" was a big mistake. I have all of my tools with 4" ports, some dual 4" ports. If you came to my shop, you could not say that a 4" port on the DC or the tool was sufficient.

This is how my review would read of the 4" ports on my equipment and DC.
Bandsaw - not enough collection; much sawdust left in the lower cabinet and falling from the upper. I have a Laguna 14/12 with 4" dust port. Could be better, but certainly is better than this description.
Tablesaw - not enough collection; mush sawdust flying off the blade at me Over blade collection (self made collector) with a shop vac and 2" hose solved this for me.
Router table - not enough, too many chips in the cabinet, not enough to run both the fence and cabinet at the same time. I use my shop vac. I have a Triton router, so under table shroud is built in. My table has a 2.5" port in the fence. Does a great job for most applications.
8" jointer - not enough, too many chips not collected in the chute but ejected at the end of the cut, chute does not clog My 2hp collector running through a SDD does a good job here. Little debris of any size outside the jointer. Chute remains clear. I used 6" from SDD 5" port (mostly flex before table saw, edge sander and jointer, hard duct and small piece of flex to Planer, Drum Sander, Spindle sander, band saw) to wye before the tools
12 1/2" planer - not enough, too many chips ejected from the loading side and/or stuck to the rollers. 5" port on my 20" planer. Very good collection.

16" drum sander - possibly (50/50 maybe better) enough. No dust in on the boards when exiting, I don't see or smell anything when using the machine. Would better/more collection improve removal from the sandpaper? I don't know.

If the DC can't pick up 99% of the chips, it isn't doing a very good job. The is 1 1/2HP top/bottom cloth bag DC with only a 4" inlet and I move it from machine to machine. Before I knew better I spent $$$ on the 4" fittings and made it stationary. More convenient with little (negative) effect on performance.

I have an older Oneida cycle I am working to assemble which has a 7" inlet. I plan to enlarge the ports on the tablesaw, jointer, and planer to at least 5". For the bandsaw and router table, I will re-plumb them so each port is connected to a larger drop or to the trunck directly.

James Gunning
07-13-2015, 6:55 PM
Allan,

Feeding from a bandsaw (or any other tool) with two 4" ports will work fine. It would flow almost as much air as a single 6" fitting.

To show some of the math: A single 4" circular duct will have a cross section of 12.56 Sq. inches. A single circular 6" dust has a cross section of 28.31 sq. inches.

David Nelson1
07-13-2015, 7:52 PM
2 horse shop fox no Wynn filter or separator 1 micron bags upper and lower. Specs claims 1550 CFM. Running 4 inch and dragging the collector around. I have a lot of 6 inch ducting but have never had the shop empty enough to plumb it.

Kent Adams
07-14-2015, 3:54 AM
I have been studying up on dust collection systems, learned lots. According to Bill Pentz's site, one should enlarge all existing 4" ports in our machines to at least 5", if we are to capture the really fine dust which is most damaging. Apparently even a short neckdown to 4" will kill the airflow to the point that the fine dust will not be captured. Has anyone here actually modified their machines to expand the dust port to 5"?

Bill Pentz never used an Oneida Smart collector. I have a 4" port PM 2000 and the DC captures the fine dust perfectly. I get 700+ CFM at the blade from a 25 foot 5 inch flex hose (with all sorts of bends) stepped down to 4" for about 2 feet and then stepped down to 3" from port to blade!

Anthony Whitesell
07-14-2015, 6:37 AM
Bill Pentz never used an Oneida Smart collector. I have a 4" port PM 2000 and the DC captures the fine dust perfectly. I get 700+ CFM at the blade from a 25 foot 5 inch flex hose (with all sorts of bends) stepped down to 4" for about 2 feet and then stepped down to 3" from port to blade!

Can you expand on how you measured an achieved this performance?

Bill Adamsen
07-15-2015, 5:45 PM
Timely question, I just performed an upgrade to my Unisaw going from 4" to 5", and switching from a portable DC (the Hitachi in the foreground) to the stationary cyclone. I've only had the machine switched over today ... so I can't provide a lot of feedback about performance. It seems to collect more dust, and more efficiently. I was surprised at the efforts to which Delta went to make the Unisaw a poor dust collection tool. Look at the first photo below. They basically constricted the opening in such a way that a hood would be inneffective. In photo 2, I removed that panel, and with a wedge similar to the piece upon which I have my hand, opened up the port to a full 5". This allowed building the hood to accept 5" hose. It is kind of a hack job but I wanted to get it done in hours not days. The fundamental issue with most tablesaws, is that they are a veritable swiss cheese of leaks, and the blades are throwing chips and dust at high velocity. Many of those leaks require creative thinking to eliminate. And the blade requires a powerful and well fitting hood. On my slider I have plugged up a number of leaks with 1/4" or 3/8" plywood "plates" and rare earth magnets. That helps. Liberal use of duct tape or foil tape also helps. It is still one of the worst offenders for dust.

Ole Anderson
07-15-2015, 6:18 PM
Kent, what are you using to measure airflow? Also confused. 4" port but reducing to 3" at blade? At guard or bottom or both? 700 cfs through a 3" will be a very high velocity

Chris Parks
07-15-2015, 8:26 PM
Hi Mike, it's because the manufacturers don't have to meet a standard for dust collection performance in NA.

Buy a Euro machine and you'll find that the ports start at 120mm, and the machines come with a performance statement as to how much dust they emit at rated airflow. The airflow is also specified in the equipment manual.

In addition, they're designed for dust collection, for example the saw will have a shroud below the blade, and there will collection above the blade.

Regards, Rod.

Rod, they might put a 5" port on the outside but my Hammer machines have 4" flex on the inside of the cabinet and I doubt the inlet under the blade has enough area to feed even a 4" line though I could be wrong there.

Chris Parks
07-15-2015, 8:31 PM
Timely question, I just performed an upgrade to my Unisaw going from 4" to 5", and switching from a portable DC (the Hitachi in the foreground) to the stationary cyclone. I've only had the machine switched over today ... so I can't provide a lot of feedback about performance. It seems to collect more dust, and more efficiently. I was surprised at the efforts to which Delta went to make the Unisaw a poor dust collection tool. Look at the first photo below. They basically constricted the opening in such a way that a hood would be inneffective. In photo 2, I removed that panel, and with a wedge similar to the piece upon which I have my hand, opened up the port to a full 5". This allowed building the hood to accept 5" hose. It is kind of a hack job but I wanted to get it done in hours not days. The fundamental issue with most tablesaws, is that they are a veritable swiss cheese of leaks, and the blades are throwing chips and dust at high velocity. Many of those leaks require creative thinking to eliminate. And the blade requires a powerful and well fitting hood. On my slider I have plugged up a number of leaks with 1/4" or 3/8" plywood "plates" and rare earth magnets. That helps. Liberal use of duct tape or foil tape also helps. It is still one of the worst offenders for dust.

Bill, there must be at least an equal inlet area into the cabinet to allow air to enter and feed the dust extraction port on any cabinet based machine.

Bill Adamsen
07-16-2015, 10:28 AM
Bill, there must be at least an equal inlet area into the cabinet to allow air to enter and feed the dust extraction port on any cabinet based machine.

Agreed ... it just seems intuitive that if most of that "air" is coming through the location where the blade/cutter is creating the dust, that the collector will be capturing the most air entrained dust.

Rick Potter
07-16-2015, 2:34 PM
I have one actual situation I can attest to. My Unisaw came with the dust collector option they used for years. It all collects at the bottom exiting to a slot in the side that has a sheet metal shroud with a 5" fitting to hook to. All factory, and I used it for years with an adaptor from 5" necked down to 4", with about five or six feet of 4" which led up to the 6" drop and 6" gate reduced to 4".

I changed the adaptor on the saw from 5" necked down to 4", to an increaser from 5" to 6", and ran 6" hose up to the 6" gate. Very wordy way of saying I replaced six feet or so of 4" with 6" between the gate and the saw. Same dust collection system.

Before: I would get gradual buildup in the bottom of the Unisaw, which eventually caused it to clog at that slot. I would then have to get a stick, turn on the DC, and stir things around down there until it cleared itself.

After: The increased air flow has kept the bottom clean except for minor spots in the corners, and I have not had a clog in the last three or four years.


PS: If anyone has this factory slot/shroud on their Unisaw......I would like to add that it is important to not allow narrow cutoffs to drop down in the saw, that helps block the slot, leading to clogs. Using a zero clearance insert is the answer to that problem.

EDIT: The wooden shroud that Bill Adamson posted above on his Unisaw is basically the same as the factory sheet metal shroud I have. They never advertised them much, but they were available.


EDIT: I just noticed this is a ten year old thread, that grew legs again. Sorry....but I guess the info is still pertinent.

Kent A Bathurst
07-16-2015, 3:14 PM
My Unisaw ~~15 yrs old, has the slot at the bottom - but it is 5" tall x cabinet width. I bought the OEM metal hood that has a 5" port.

Laughable performance. Unisaws of that era used "dust collection" as a marketing department gag line.

But - - A few hours and a couple bucks later, it was very good.

As noted above, you do need inflow capability equal to volume being drawn out. A bit - not a lot - will go though the slot in a ZCI. Not nearly enough.

The game is to supply that volume - and ONLY that volume - in a controlled manner. My version of reality:

1. Expandable foam between cabinet and table top. Incredible gaps there. Seal them all up.
2. Foam weatherstrip around motor cover.
3. Caulk around the 4 edges of the cabinet floor - where it meets the cabinet sides. Plug all that up.
4. Metal tape over all the extraneous holes in the cabinet - there for various possible accessories, I guess? Including tightly around the gasket where the power cord enters the cabinet.
5. Magnetic sheet to cover the travel slot the height wheel traverses when you tilt the saw.

That got it all blocked up really well. Now - to put the air in, where I want it in.....

In the motor cover, using drill and bayonet saw, I cut thee horizontal, parallel, slots - 1/2" wide and averaging about 9" long. This is the entry for the air -- it is crossing the motor, keeping dust off the motor and the trunnion, and cooling the motor at the same time.

area of 5" pipe to DC = 19.5 sq in.
three slots @ 1/2" x 9" = 13.5 sq in.
The other 6 sq in of required air inlet ..... well, some comes through the ZCI, and some comes through leakage I did not catch, or did not perfectly plug up. And the mag sheet over the travel slot for the crank - - it is not a perfect seal.

A little bit of dust builds up in the corners, but I have never had to clean out the cabinet since the day I did this. Was prepared to enlarge the slots if needed, or to put tape or mag sheet over slots if needed, but I hit first try - sheer luck.

I originally was thinking about putting a slot across the cabinet, opposite the dust hood, just above the angled cabinet floor - send air down across the floor, straight at the dust hood. Never did it because the first step solved it, and I like the idea of blowing dust off the motor.........

Allan Speers
07-16-2015, 5:53 PM
As noted above, you do need inflow capability equal to volume being drawn out. A bit - not a lot - will go though the slot in a ZCI. Not nearly enough. .


How about drilling a bunch of holes into the ZCI?

Think about it: The purpose of the insert is to keep small slivers from falling in, but it also stops a lot of airflow, right where you need it. A bunch of holes would not change that functionality.

Heck, you could probably even make a ZCI out of some kind of thick, course screen, or maybe an aluminum torsion box of sorts, for more strength.

Chris Parks
07-16-2015, 11:03 PM
No air enters from the blade opening in the table once it is covered during cutting so that must be allowed for. Another thing is all dust extractors are not created the same,I might be talking of 1500 CFM and others of half that so the results vary even with the best of intentions and knowledge.

Michael W. Clark
07-17-2015, 10:01 PM
I would add that your area for allowing air to come in doesn't really need to equal the area of the exhaust duct. With most exhaust ducts you are running 3500 to 4000 FPM to keep the dust entrained and not falling out in the ductwork. If you can keep 2000 FPM through all the slots, you should be good to go. Therefore, if your open area is double the exhaust duct area, it should be fine. I do think it is good to try and direct the inlet air if there is excess area that would allow it short circuit (go straight in the duct without picking up any dust). Air will take the path of least resistance, so the velocity through all openings may not be equal.

Mike

Kent Adams
07-18-2015, 6:59 AM
Can you expand on how you measured an achieved this performance?

Borrowed an anemometer from a friend to measure CFM. I didn't really achieve the performance through anything I did, I give all the credit to the DC I have, which works differently than most.

Kent Adams
07-18-2015, 7:20 AM
Kent, what are you using to measure airflow? Also confused. 4" port but reducing to 3" at blade? At guard or bottom or both? 700 cfs through a 3" will be a very high velocity

Hi Ole, the powermatic 2000 saw has what appears to me 3" hose, the manual doesn't give the size, but its smaller than 4" and larger than the hose on a Shop Vac, that extends from the 4" port to a dust chute that is below the blade. I used a friends anemometer to measure the CFM where the blade meets with the dust chute. The Oneida Smart DC has a variable motor that adjusts to the hose size. At least that's how I understand it works http://www.oneida-air.com/pdf/smart-portable-3-hp-quick-quote-2014-web.pdf

Oneida claims that the DC will produce 766 CFM with a 5" flex hose at 10 feet. My DC is only about 5 feet from the TS, but I have 25 feet of 5" flex hose, which probably constricts to 20ft when the DC is turned on. I'm no expert on dust collection by any means, so I can't tell you how it does it, but 700 cfm is what I measured at that dust shroud/chute at the bottom of the blade. This is the first DC, other than a shop vac that I've owned so I don't have anything to compare it with. The thing sounds like a jet engine when you turn it on. I did not measure the CFM at the top of the throat, I suspect its considerably less. I can say that there is no fine dust settlement on the saw table top after cutting several board feet, but there is the occassional larger size chips, but not enough to fill a teaspoon.

Michael W. Clark
07-18-2015, 7:38 AM
I did not measure the CFM at the top of the throat, I suspect its considerably less.

Flow will be the same at all places, but the velocity will be higher in the smaller duct.

Ole Anderson
07-18-2015, 7:35 PM
How about drilling a bunch of holes into the ZCI?

Think about it: The purpose of the insert is to keep small slivers from falling in, but it also stops a lot of airflow, right where you need it. A bunch of holes would not change that functionality.

Heck, you could probably even make a ZCI out of some kind of thick, course screen, or maybe an aluminum torsion box of sorts, for more strength. Something like this?:

Chris Parks
07-18-2015, 8:30 PM
I can't see the advantage or even need for holes in the ZCI as it get covered up and flow stops when a cut is being done in a lot, most? cases.

Anthony Whitesell
07-18-2015, 10:35 PM
Borrowed an anemometer from a friend to measure CFM. I didn't really achieve the performance through anything I did, I give all the credit to the DC I have, which works differently than most.

The anemometer was reading more than 90 miles per hour or 8000 feet per minute?

Michael W. Clark
07-19-2015, 8:25 AM
The anemometer was reading more than 90 miles per hour or 8000 feet per minute?
It could have been a Hotwire anemometer and it would be 14,000 fpm if all was going through the 3". That seems awfully high.

Ole Anderson
07-20-2015, 10:28 PM
I measured 11,250 fpm on a 3.5"opening. 2 HP Oneida SDG. Using this gauge but upstream with hose removed. 14,000 does seem high, but not out of the realm of possibility.

Rod Sheridan
07-23-2015, 3:11 PM
What does the statement for your machine indicate it emits for the various functions?

Hi Phil, sorry it took so long to reply.

Here's the statement on dust emissions.

"The machine was tested for particle emissions according to DIN33893. The Wood Authority ascertained, according to the "Principles for Testing Particle Emissions" (workplace-related particle concentrations) of woodworking machines, that the particle emission values for this machine are notably below the currently valid atmospheric limit of 2.0mg/cubic metre. This is certified by the blue label "BG Wood Particle Tested"

The flow rates for the machine are specified as

Device Air Speed (m/s) Vacuum (Pa) Port size (mm)

Saw Cabinet 20 1824 120

Saw Guard (overhead) 20 935 50

Shaper hood 20 770 120


The shaper and saw are rated for 790 cubic metres/hour and 814 cubic metres per minute.

Regards, Rod.

Phil Thien
07-23-2015, 4:40 PM
Hi Phil, sorry it took so long to reply.

Here's the statement on dust emissions.

"The machine was tested for particle emissions according to DIN33893. The Wood Authority ascertained, according to the "Principles for Testing Particle Emissions" (workplace-related particle concentrations) of woodworking machines, that the particle emission values for this machine are notably below the currently valid atmospheric limit of 2.0mg/cubic metre. This is certified by the blue label "BG Wood Particle Tested"

The flow rates for the machine are specified as

Device Air Speed (m/s) Vacuum (Pa) Port size (mm)

Saw Cabinet 20 1824 120

Saw Guard (overhead) 20 935 50

Shaper hood 20 770 120


The shaper and saw are rated for 790 cubic metres/minute and 814 cubic metres per minute.

Regards, Rod.

Interesting. So the 790 and 814, are those really cubic meters or did the manufacturer convert to CFM, or maybe those are Vacuum #'s?

In any event it is nice that they can provide those emissions values, that is neat!

Rod Sheridan
07-23-2015, 8:33 PM
Sorry Phil, those are cubic metres per hour........Rod.

Chris Parks
07-23-2015, 8:56 PM
Phil, how much does the average dustbin collector pull out of the total flow of a shop vac?

Phil Thien
07-23-2015, 9:45 PM
Phil, how much does the average dustbin collector pull out of the total flow of a shop vac?

I'm not sure what the question is, but if you're asking how much a trash-can separator reduces total airflow, it is quite a bit. And a lot depends on how large your separator is, and how large a shop-vac you're using.

That is because the resistance is proportional to the airspeed squared. So a larger separator means a slower spin (lowering resistance), but a larger vac (more CFM typically) means a faster spin (and higher resistance). And you can't just keep using a larger separator because that reduces separation rates. And you can get to a point where larger vacs are just wasted, the separator will just eat-up any increase.

So a balancing act, for sure.

Buzz Coren
11-08-2023, 8:52 AM
I have two Rikon 10" bandsaws, a 10-306 and 10-306-1. I never liked necking down to the small dust port (especially on the 306-1 that's used the most), it's way too restricted airflow and I decided to enlarge the hole, with three pleasant surprises that made it rather easy. Surprise #1: after removing the dust port adaptor I found the actual hole nearly matches the I.D. of my 3" pvc ducting. Surprise # 2: the metal blast gate fit nicely beneath the machine base as if it were meant to mount there, in perfect alignment with pvc pipe to the dust port hole. I removed two screws from the housing, used it as a template for two holes drilled in the base and mounted it semi-securely with sheet metal screws into the base. Surprise # 3: when the pvc pipe was cut to size the bottom two holes for the adaptor removed earlier lined up exactly with the pipe's 1/4" thick shoulder, allowing two small sheet metal screws to further secure it to the saw after two tiny holes were drilled into the shoulder. This tightened up the whole assembly rock solid. I suppose I could caulk around the connection inside and out but it's so close already I doubt I will....the lower wheel space hasn't a speck of dust after many cuts compared to before with the little dust port. It took about one hour. I plan to repeat this with my 10-306 but it's the older version with a welded-on dust port and will involve some difficult surgery, need to think that through first. I'm happy with the result, my DC seems as though it's happier too. Photos show the stripped-down sequence.