have sheet metal, need hole.

Discussion in 'The Garage' started by Bloodweiser, Nov 10, 2012.

  1. MotorradMike

    MotorradMike MIL-TFD-41

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    Is there a reason you can't use aluminum?
    Things get easier.
    #21
  2. speedracertdi

    speedracertdi Been here awhile

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    Jigsaw, fine tooth blade, and a little WD-40. You'd be there all week with a Dremel.
    #22
  3. josjor

    josjor Long timer

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    With the tools you have I would just chain drill it.

    1. Mark your 3 3/8 circle.
    2. Use an 1/8" bit to drill a series of holes that touch/almost touch around the INSIDE perimeter of your mark.
    3. Once you're all around the circle, you can knock out or wiggle the piece to remove the center.
    4. Smooth and fit the final hole with a half-round file.

    Should take you about 15-20 minutes with a good bit. Over the course of four years in the USAF working on bombers and tankers I would be afraid to count the number of holes I've cut this way.
    #23
  4. jules083

    jules083 Long timer

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    You need one hole right? Ever plan on drilling a hole that size again?

    Go to a machine shop. By the time you mess around with getting it 'close' you should be able to get it done for a few dollars.

    Otherwise I'd probably chain drill it or use a jigsaw. I'd probably make a practice cut inside the hole with a jigsaw to see how it looks then go from there.
    #24
  5. LuciferMutt

    LuciferMutt Rides slow bike slow

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    For round holes in sheet metal, use a chassis punch of the desired size. See here: http://www.mcmaster.com/#chassis-punches/=k4qaw6
    (shipping is fast from this company)

    Taking it to a machine shop is very likely to have you end up paying a minimum one hour charge which will be at least $60, unless the shop is small and has nothing else to do or you know somebody who works there. This is especially true if you ask them to do both the hole and the rectangle cutout. A waterjet shop is almost certain to charge you a minimum one hour fee. The abrasives in the water are not cheap and they are generally not reclaimable.
    #25
  6. bomber60015

    bomber60015 tikkun olam

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    +1 on aluminum -- it works very nicely with woodworking tools (lower the speed), and looks great - - - - I grok using material that's on hna, but there no need to make things tough on yourself . . ..
    #26
  7. H96669

    H96669 A proud pragmatist.

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    Go buy one of them diamond coated round hack saw blades.About $5.00 or less. Drill one hole about 1/2", put blade through and install on hack saw. Cope away....!
    #27
  8. anonny

    anonny What could go wrong?

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    Scroll saw, jig saw.
    #28
  9. ttpete

    ttpete Rectum Non Bustibus

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    They want $320 for a 3" Greenlee punch.....:eek1

    If there's only one hole, I'd buy a Harbor Freight jigsaw and cut it and then have a jigsaw for other projects.
    #29
  10. P B G

    P B G Long timer

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    Just buy an appropriate hole saw, Then use it to drill a hole through 1/2" wood (plywood is fine).

    Clamp the plywood over where you want your hole, and remove or shorten the central drill so it doesn't protrude too far, you want the hole-saw into the plywood before you start.

    Second the handle to keep it from torquing on you, but in addition to the plywood you won't wander off center on the material.
    #30
  11. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Damn...yep. I missed the part about how big the hole needed to be.


    Hole saw will work OK if you have a big variable speed drill with a secondary handle arm on it. Turn it slowly and use WD-40 on the cutting area.
    #31