View Poll Results: Which option?

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  • 5" hose to 4" port on tool

    8 32.00%
  • 5" hose / increase tool port to 5"

    6 24.00%
  • 5" hose / increase tool port to 6"

    1 4.00%
  • 5 to 6 on SDD / 6" hose / 6" tool port

    4 16.00%
  • Stay with 4" all the way

    6 24.00%
Results 1 to 11 of 11

Thread: Dust Collection - hose / port size comparison

  1. #1
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    Dust Collection - hose / port size comparison

    I've always had a 4" flex hose going from my super dust deputy to my table saw. The performance has been good, but I didn't know what I was missing. I was working on my dust collector and at the bottom of the SDD it has a 6" port that drops down to the collection bin, and holy crap the amount of air it moves in the 6" port compared to my choked down 4" port was mind blowing.

    With that being said I'm looking to re-evaluate my ductwork and how I connect to my tools. I've made a graphic that illustrates all my options going forward and I'm looking for feedback on which one will provide the best air-flow and not cause a drop in CFM which will not have enough to keep the dust/chips aloft.


  2. #2
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    6" port in the cabinet which you will have to cut in and six inch hose as short as possible onto six inch solid ducting. You will need to supply make up air to the cabinet to get the full benefit, I left the original port open for the make up air and cut the 6" port for extraction. Works every time but the make up air is the secret.
    Chris

    Everything I like is either illegal, immoral or fattening

  3. #3
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    Quote Originally Posted by Chris Parks View Post
    6" port in the cabinet which you will have to cut in and six inch hose as short as possible onto six inch solid ducting. You will need to supply make up air to the cabinet to get the full benefit, I left the original port open for the make up air and cut the 6" port for extraction. Works every time but the make up air is the secret.
    That was my initial thought, but I'm wondering if when the pipe gets reduced from 6 to 5 at the super dust deputy if that will kill the air flow for the overall run and cause the airflow to be too slow to support 6" ducting. What do you think?

  4. #4
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    You really haven't provided quite enough information to answer the question very specifically. What type of dust collector do you have? What is the air flow rating in CFM? How long are your runs? I would run the same size hose as what is on the dust collector if the runs aren't too long. One thing I can tell you without the slightest hesitation is that the performance of your system will increase significantly if you will get rid of the flex hose and use a smooth sided duct instead. That flex hose robs you of a tremendous amount of air flow.

  5. #5
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    I went with a 5" hose from a 6" sub-main and used a bell mouth cut into where my old 4" hole was in the bottom of my G1023. Probably the same as option 3. Got the 5" bell mouth from Penn State. My saw must move front to back to either make room or to rip 8 foot lumber, so I required the flex. Older pic before I put down a new floor and got my SharkGuard plumbed with a 3" hose up to the pipe that you see.
    Attached Images Attached Images
    Last edited by Ole Anderson; 01-07-2015 at 11:38 PM.
    NOW you tell me...

  6. #6
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    Quote Originally Posted by Art Mann View Post
    You really haven't provided quite enough information to answer the question very specifically. What type of dust collector do you have? What is the air flow rating in CFM? How long are your runs? I would run the same size hose as what is on the dust collector if the runs aren't too long. One thing I can tell you without the slightest hesitation is that the performance of your system will increase significantly if you will get rid of the flex hose and use a smooth sided duct instead. That flex hose robs you of a tremendous amount of air flow.
    Correct, I plan to use smooth walled ducting and flex hose for the final connection. The diameter was the main point, sorry I should have clarified that in the graphic. The runs should be approximately 10-20 feet.
    The dust collector is a Grizzly G1029Z2: https://www.grizzly.com/products/G1029Z2 They claim 1550 CFM but obviously that's not a realistic number since they're all bogus. Don't have a way to measure it unfortunately.

    Quote Originally Posted by Ole Anderson View Post
    I went with a 5" hose from a 6" sub-main and used a bell mouth cut into where my old 4" hole was in the bottom of my G1023. Probably the same as option 3. Got the 5" bell mouth from Penn State. My saw must move front to back to either make room or to rip 8 foot lumber, so I required the flex.
    That's a great idea, thanks I'll save that for future.
    Last edited by Ian Scofield; 01-07-2015 at 11:38 PM.

  7. #7
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    Oct 2006
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    Ole, Why put the thumb screw on the blast gate towards the saw?
    Glad its my shop I am responsible for - I only have to make me happy.

  8. #8
    which one will provide the best air-flow and not cause a drop in CFM which will not have enough to keep the dust/chips aloft
    Forgive my throwing a little math into the discussion. For chips/heavier dust particle pickup, and vertical runs, you need and airspeed of 3700 fpm. cfm = fpm*area (of duct). The cross section area of 6" pipe is ~ 0.2 sqft, so 3700*0.2 = 740 cfm needed. Even with the bloated claims of air flow (personally, I think HF is the most outrageous!), your Grizzly has more than enough power to support 6" ducts/hoses.

    That said, your option 4 would give the best performance, but do you really want to go to the trouble of increasing the size of the port in your table saw?
    I'm wondering if when the pipe gets reduced from 6 to 5 at the super dust deputy if that will kill the air flow for the overall run
    Any reduction in pipe size will diminish air flow to some degree, but a reducer like that wouldn't "kill" air flow- certainly not as much as having a 5" pipe the whole length.

    The analogy I see is a tool with, say, a 14 gauge power cord. You will lose less power being fed to the motor by plugging into a 20 amp circuit (with 12 gauge wire running from the breaker box) than you would into a 15 amp circuit (with narrower 14 gauge wire). IOW, you have greater resistance of thinner wire for a short length, rather than the whole run, just like a reducer just at one end. I think the easiest way of improving performance would be to have a 4" to 6" adapter at the saw, 6" hose, and a 6" to 5" reducer at the Super Dust Deputy.

    For my own curiosity, what precisely do you mean by the "holy crap amount of air it moves in the 6" port"? Do you mean the airflow inside the bottom of the cyclone, where the dust drops out (i.e., the neck of the "funnel")? It's my understanding of cyclones is that as air spirals down the funnel, the air flow stays more or less the same, but the air speed increases as it get further down. Could you be feeling increased air speed, which is a normal result of cyclone geometry, and may have nothing to do at all with the hose size of your table saw connection? Just my .02

  9. #9
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    Any ducted system is limited by the smallest port it has to pass air through. The Australian WW forums have got a heap of serious and well researched information on DE and apart from Bill Pentz's site are the best place to read about this stuff.
    Chris

    Everything I like is either illegal, immoral or fattening

  10. #10
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    Quote Originally Posted by Mike Heidrick View Post
    Ole, Why put the thumb screw on the blast gate towards the saw?
    See the gap between the gate and the hole it slides into? In the position shown the thumbscrew pushes the gate closed toward the inlet, if it were on the other side it would force a gap on the suction side and cause a leak in the system. I only need the screw to hold the gate in the up position. On my MS there is enough friction to hold it in place and I don't need to engage the screw to hold it open. The suction will pull the gate toward the pipe opening when closed, thereby sealing off the gate. Two of my gates are in a horizontal position, here I use the thumbscrew on the bottom to push the gate up and hold it closed, although the suction would probably do that anyway.
    Last edited by Ole Anderson; 01-08-2015 at 9:43 AM.
    NOW you tell me...

  11. #11
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    Austin, TX
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    Quote Originally Posted by John Donhowe View Post
    Forgive my throwing a little math into the discussion. For chips/heavier dust particle pickup, and vertical runs, you need and airspeed of 3700 fpm. cfm = fpm*area (of duct). The cross section area of 6" pipe is ~ 0.2 sqft, so 3700*0.2 = 740 cfm needed. Even with the bloated claims of air flow (personally, I think HF is the most outrageous!), your Grizzly has more than enough power to support 6" ducts/hoses.

    That said, your option 4 would give the best performance, but do you really want to go to the trouble of increasing the size of the port in your table saw?
    Any reduction in pipe size will diminish air flow to some degree, but a reducer like that wouldn't "kill" air flow- certainly not as much as having a 5" pipe the whole length.

    The analogy I see is a tool with, say, a 14 gauge power cord. You will lose less power being fed to the motor by plugging into a 20 amp circuit (with 12 gauge wire running from the breaker box) than you would into a 15 amp circuit (with narrower 14 gauge wire). IOW, you have greater resistance of thinner wire for a short length, rather than the whole run, just like a reducer just at one end. I think the easiest way of improving performance would be to have a 4" to 6" adapter at the saw, 6" hose, and a 6" to 5" reducer at the Super Dust Deputy.

    For my own curiosity, what precisely do you mean by the "holy crap amount of air it moves in the 6" port"? Do you mean the airflow inside the bottom of the cyclone, where the dust drops out (i.e., the neck of the "funnel")? It's my understanding of cyclones is that as air spirals down the funnel, the air flow stays more or less the same, but the air speed increases as it get further down. Could you be feeling increased air speed, which is a normal result of cyclone geometry, and may have nothing to do at all with the hose size of your table saw connection? Just my .02
    Ive seen the math before, read bill Pentz site quite a few times to wrap my head around it all and plan for a future system some day.

    I understand and the electrical reference, however bill pentz site describes how air at low pressure isn't compressible so any form of reduction or obstruction isn't as easily overcome like it would if the medium were water. I may grab some 6" PVC and give that a go.

    With regards to the cyclone it makes sense that the velocity of the air would increase as the CFM remains the same. My comment was just noticing that in working on my old HF dust collector and with the new grizzly motor, and feeling the air flow from the 6" inlet on the grizzly. Then feeling it as it sucked in from the bottom of cyclone when I didn't have the collection barrel attached, so it was essentially a 6" duct run from the motor for about 2 feet. The air flow was incredible compared to my 10' long 4" diameter flex hose run to the table saw. This is what sparked my interest in looking in other piping to increase the overall air flow of the system and squeeze more performance out of the upgraded motor.

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