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Thread: modification to DC inlet -- good idea? or not?

  1. #1

    modification to DC inlet -- good idea? or not?

    I have had my new 2 HP single stage canister DC (Grizzly g0548z) set up for seven months now and really like it.

    With a true 2 HP (240 v, 9 amp) motor and a 12-3/4" dia. steel impellor, it really sucks!

    g0548z.jpg

    I have it set up as shown with the metal three way 'Y' screwed in place, and three blast gate isolated 4" flex hose branches going directly to my TS, SCMS, and jointer/planer station. Though not ideal, the 4" flex branches are pretty short and I usually run the DC with two gates open and one closed.

    All has been going well untill last week when I was jointing and planing some 2x SPF stock. Though I was taking light cuts (~1/16" on the jointer and 1/16" on the planer), I was stuffing the lumber through the planer in rapid succession and managed to plug up that branch.

    Disasembly quickly revealed that the waste was not dust and chips, but rather "shreds" (1"+ long x ~1/4" wide) and these had hung up around the cage that covers the blower inlet, untill the inlet was completely plugged.

    dc.JPG

    Once the blower stopped moving air, the elbows at the machine connections quickly packed full of shredded wood waste as well.

    So I am contemplating cutting this cage out of the blower inlet and relying on brain cells to prevent me from sending any anvil size chuncks into the blower.

    Any thoughts?
    Last edited by Matt McColley; 07-24-2012 at 2:12 PM.

  2. #2
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    I don't see any other way around it if this is going to become a regular problem. If I were you maybe I'd work again under similar situations to see if it repeats or not.

    that said, I made the same mod to my harbor freight, but I didnt cut off the screen... I was simply making my own 6" intake and didn't bother adding my own screen (too worried it would come lose and itself be an issue).

    I recommend against using the DC to cleanup the floor if you do this... in addition to the risk of sparks/fires, I think the bigger and more likely issue is sucking up something like a tape measure and having that do a number to your impeller (not to mention scaring the life out of you!). Crazy how loud just a paper towel can be hitting the impeller.

    If you are just using the DC hooked up to machines, and won't ever operate the thing without ducting its probably not a big deal.... The over worrier in my would also like to see you attach at least a 1 foot long section of hard pipe to the intake if you remove the screen... just incase somehow a neighborhood toddler were to lock himself in your garage and somehow turn it on! (yes you laugh but this happened to my brother when I was a kid, locked in a strange garage full of tools, parents waited for fire dept but ended up breaking in). the length of pipe would prevent prying hands from reaching in all the way etc.

  3. #3
    I have to laugh about the kid locked in the garage comment.....

    When I unplugged the pipes and was cleaning up the mess, I was tossing hand fulls of debri into the intake (removed the 'Y') and was thinking that I might just be stupid enough to get my hand sucked into the impellor some day.

    If I do have a repeat performance and decide to modify the cage, maybe I could just cut two of the five support legs and see if that cures the problem.

  4. #4
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    not a bad idea.

    I was too young to understand at the time but it was pretty scary for my parents... at first they fed him cookies through a small gap in the garage door in hopes of keeping him distracted from touching all the tools. they were trying to buy time for the fire department to arrive. after about 10 minutes another neighbor said "screw this" and just busted a window into the house. when the owner of the house actually came home... he was surprised they even waited 10 minutes to break a window. it happened because my brother slipped in while the neighbor was pulling their car out, shutting the door behind.

  5. #5
    him cookies through a small gap in the garage door in hopes of keeping him distracted from touching all the tools.
    I'm sorry .... but I can't stop laughing to picture this... not funny for your parents or your brother at the time I'm sure....

  6. #6
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    I had a 1 hp Penn State 2 bagger and had the same problem, ended up cutting out the grill to solve the problem. No such problem with a cyclone as the fan is after the bin. Suck up a tape measure? No problem just fish it out of the bin. But with a 2 hp like you have, you may never need to go that route as long as you keep your ducts big enough and remove the screen, AND BE CAREFUL AS PREVIOUSLY STATED.

  7. #7
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    Experience (mine anyway) suggests that even a seemingly quite heavy gauge steel impeller may get hit hard enough to knock it out of balance if it swallows a chunk of wood - it happened with a bagger I ran for years, and the resulting vibration bugged the hell out of me.

    There's no very obvious answer other than that the impeller needs to be heavily built enough to tolerate anything the system can pull in to hit it. The basic thinking with radial impellers of this type is that they are suppose to be able to pass anything that comes through. That's normally why their very high levels of inefficiency are tolerated.

    It's likewise pretty clear that planer shavings are always going to hang up on anything like a grid, and that if hand access is a concern that a better solution would be the permanent attachment of a long enough inlet stub. Which probably isn't an attractive proposition, if only because it'd bump up shipping costs.

    The grid is to my mind a calculated cop out by the maker - a bit similar to the pretty much unusable safety devices that come on some low budget equipment. They force you to take them off to use the equipment, but in doing so you create a ready made and very robust defence for the manufacturer in the event of any claim subsequently arising.....

    A long shot, and it'd burn up some of the available pressure/suction capability. Plus I'm not sure what shape might work best - but one option might be to install some sort of drop out pot/chamber before the fan inlet. It wouldn't need to be all that sophisticated to capture the sort of heavier chunks of wood likely to do damage, and it'd double if permanently attached as a hand safety device too.

    It'd need careful testing and sorting out, as it wouldn't do if it was inclined to fill up with chips and dust - that's be a fire risk.

    Perhaps something based on a 45 deg T with a removable cap on the branch....

    ian
    Last edited by ian maybury; 07-24-2012 at 6:21 PM.

  8. #8
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    I cut out the grill on my little bagger and it has survived for 7 or 8 years. I use it exclusively on the jointer and sander.
    Buy a man a plane ticket and he’ll fly for a day.
    Push a man out of a plane
    and he’ll fly for the rest of his life.

  9. #9
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    I use mine on a shaper, the shaper can take a bite out of wood when you were not planning on it. So I left the bars in and put a preseperator in line, problem solved. It makes emptying the bag much easier too, because I almost never have to!

  10. #10
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    Yep, Peter is on the right track with this. Just build a pre-seperator (like a Thien baffle, for example) and you're good to go.

  11. #11
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    I wondered as I was reading this thread, just how far before I'd get before someone would recommend a separator.

  12. #12
    I have the fabrication of a Thein plate to put just above the chip bag (to help keep the filter from plugging up) on my short list of projects to get to.

    I've considered a pre-seperator, but for two reasons, have steered away from that solution...

    1.) my floor space is very limited
    2.) they all seem to be based on 2.5" or 4" inlets (I don't think I've seen a Thein seperator with a 6" hole)

  13. #13
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    You can make a separator to match any size piping. Properly configured, it takes up no more floor space that your current dust collector. With a top hat style separator, the motor/impeller unit is mounted above the separator/collection can so the foot print pretty much the same. Some have modified the cart to hold it this way and keep the unit mobile, while some wall mount it and make it stationary (as I did). I need to take some more pictures, but here is two. One on the separator with the lid off, and one of everything mounted in my dust collection annex.

    I'm also sending you a link via PM to a detailed top hat build that I used as a guide to build mine. I changed/improved a couple things on mine. I used aluminum flashing to line the interior wall, and I built a block to hold/house the inlet pipe that filled in the area around the pipe inside the separator to help reduce turbulence.
    Attached Images Attached Images

  14. #14
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    A Thien style pre-separator will fix your problem. I know it fixed mine.

    There are many different ways to build them. I chose to build mine based on a 55 gallon drum with 5" side inlet, no top hat. I have not yet spun my impeller housing to sit above the can. But that is in the planning stages. I was planning on building a custom stand, however my machine never moves, so wall mounting might not be a bad idea after all...
    Trying to follow the example of the master...

  15. #15
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    Quote Originally Posted by Matt McColley View Post
    I've considered a pre-seperator, but for two reasons, have steered away from that solution...

    1.) my floor space is very limited
    2.) they all seem to be based on 2.5" or 4" inlets (I don't think I've seen a Thein seperator with a 6" hole)

    IMHO a pre-separator is the cheapest and best way to solve your problem. As Kevin pointed out, floor space will not be affected and any size pipe will work (as long as it's close to your machine's inlet size). Thus, 6" pipe is not a problem in your case. In fact, go to Phil Thein's message board ( http://www.cgallery.com/smf/index.php?board=1.0 ) and take a look at the many examples where people used 6" pipe and have had absolutely no issues in doing so.

    The main concept to keep in mind here is that you want the shavings to be contained before they even come near your impeller... so, short of shelling out the cash for a cyclone, a pre-separator is the best way to do that.

    Just tryin' teh hep.

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