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Thread: cutting a hole in DC duct??

  1. #1
    Join Date
    Mar 2008
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    Between No Where & No Place ,WA
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    cutting a hole in DC duct??

    Colleagues: I need another DC line for a TS over the blade dust collection/blade guard.

    To run it off the existing 6" TS DC duct, need a hole in the duct then install a saddle tap Y connector on the 6" duct. See:
    www.oneida-air.com/inventoryD.asp?item_no=SCOLLECT33

    Seems to be rather straight forwarded, but how-in-the-heck do I cut the hole in the existing 6" diameter duct?

    Considered a 6" 45 degree Y -- See: https://www.oneida-air.com/inventory..._no=SCOLLECT41 -- but I would need to dismantle the existing duct and blast gate to install it.

    Any ideas?


  2. #2
    Join Date
    Jun 2015
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    I say dismantle. Ive had to deal with this too for various reasons. Just the rest of the shop, the dust collection can be an every changing setup.
    If at first you don't succeed, redefine success!

  3. #3
    Drill a hole and go at it with Tin snips. It doesn't take long with a good pair of snips.

  4. #4
    Hole saw. Extra characters.

  5. #5
    Quote Originally Posted by Darcy Warner View Post
    Hole saw. Extra characters.
    Really? Seems like a giant pain to make an oblong hole with a holesaw

  6. #6
    Join Date
    Sep 2015
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    Use the wye as a template and use a magic marker inside to draw the oblong. Then, as Martin said, drill a hole and use aircraft shears. It is about a 5 minute job.

  7. #7
    The hole doesn't need to be round or oval. Rectangular/ square will work as long as there is enough metal left to screw/pop rivet the saddle to the original pipe and goop your favourite gorilla snot between.

  8. #8
    Join Date
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    M. Wasner and B. Rogers: Tin snips--which I have -- came to mind right-off-the-bat with a hole drilled to start the cutting.

    But-- and there always is a "but"-- are there specialized snips to cut a circular/oblong hole??

  9. #9
    Join Date
    Sep 2016
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    Use a hole saw and touch up the taper on the edges with a soldering iron. If it is metal duct use tin snips.
    Bill

  10. #10
    Quote Originally Posted by Ray Newman View Post
    M. Wasner and B. Rogers: Tin snips--which I have -- came to mind right-off-the-bat with a hole drilled to start the cutting.

    But-- and there always is a "but"-- are there specialized snips to cut a circular/oblong hole??
    I used the offset handled ones. Nothing special other than that

  11. #11
    Yeah, drill a 6" hole and finish up the shape with some snips. Quicker than drilling a small hole and trying to cut the whole thing out with snips.

  12. #12
    Join Date
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    E TN, near Knoxville
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    Quote Originally Posted by Martin Wasner View Post
    I used the offset handled ones. Nothing special other than that
    Same here for sheet metal. I drill maybe a 1/2" hole and then cut from there (assuming there is enough clearance around the duct to use the snips). You only need a hole big enough to get the tips of the snips started. If you have one a powered nibbler will work too. A jig saw with the right blade is an option but can be harder to get the hang of for sheet metal. A multi tool will probably cut it but I haven't tried that.

    I keep tin snips in left-hand, right-hand, and straight blades. The left or right are easier for a curve. (I also use Jet pneumatic snips when I have a lot to cut - fast and effortless.)

    I would want a hole larger than the opening in the wye connector. Or just cut out a section and add a wye.

    JKJ

  13. #13
    Join Date
    Sep 2015
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    Quote Originally Posted by Ray Newman View Post
    M. Wasner and B. Rogers: Tin snips--which I have -- came to mind right-off-the-bat with a hole drilled to start the cutting.

    But-- and there always is a "but"-- are there specialized snips to cut a circular/oblong hole??
    Yes, there are "aircraft shears" that either cut to the right or to the left (and one version straight ahead). Under $10 IIRC at Harbor Freight. "tin snips" do best cutting straight.

  14. #14
    Join Date
    Sep 2015
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    BTW, I watched some "professional" HVAC guys cutting in to a metal duct. They took a screw driver and a hammer and wacked the screw driver on it's side to tear a hole. Then they went in with aircraft shears. Badda boom, badda bang. The hole was done in 60 seconds. A couple of years later I was adding a central AC and needed to cut into a plenum. Out comes a screw driver and hammer. Badda boom badda-bang. 60 seconds - - all done.
    No need to over think... ;-)

  15. #15
    Join Date
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    I used a step drill--Harbor freight--1/4" to 3/4"--to make access opening. Overlay the saddle in position, trace the inside as Brice said, drill the access hole and tin snip the oblong opening. Paint on duct sealer and pop rivet. should be easy and quick to do.

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