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Thread: Is a unibit good for drilling 3/16" steel?

  1. #1
    Join Date
    Oct 2006
    Location
    Minneapolis, MN
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    2,701

    Is a unibit good for drilling 3/16" steel?

    Is a Unibit a good idea for drilling holes in 3/16" steel, or am I better off buying the correct size twist bit? The holes are 3/4" diameter. I have used my Unibit to make a fairly large hole in steel before, but it was only 1/16" thick.

  2. #2
    NO
    the maximum would be 1/8"
    Step Thickness 1/8 in
    http://www.cesco.com/b2c/product/322316

  3. #3
    Join Date
    May 2006
    Location
    Colorado
    Posts
    238
    Depends on how many you are planning on making. I've used them before on steel up to 1/4" thick. If the material is thicker than the step you need to drill from both sides of the material to the center.

  4. #4
    Join Date
    Feb 2003
    Location
    Hayes, Virginia
    Posts
    10,290
    Yes
    Take a look at the cheap step drills from Harbor Freight, with the three piece set each drill has more steps which provide for deeper drilling in thicker material. I recently drilled over a hundred 1/2" diameter holes in 3/8" steel plate for a pulverizer I was building for my tractor. Today I am using the same drill bit to drill 1/2" holes in 6" heavy wall steel pipe making new supports for my work shop.

    http://www.harborfreight.com/3-piece...lls-91616.html

    The trick is to find the right size unibit for the job but even if you have to drill from both sides they sure save time.
    .
    Last edited by Keith Outten; 01-29-2013 at 9:09 AM.

  5. #5
    Join Date
    Oct 2006
    Location
    Minneapolis, MN
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    2,701
    Why do Unibits save time? Is it because they have the steps and don't drill the full hole size at once? My only reason for using a Unibit is because I already have one and I would like to avoid the cost of 3/4" drill bit if I can. I need to drill 8 holes.

  6. #6
    Join Date
    Sep 2010
    Location
    Conroe, TX
    Posts
    179
    You didn't mention if you were hand drilling or using a press. One nice thing about unibits is that they make a round hole, even in thin sheet metal. Normal two flute drill bits tend to make triangular holes when done by hand. At 3/4" even 3/16 steel can behave like thin sheet metal.

  7. #7
    Join Date
    Oct 2006
    Location
    Punta Gorda, Florida
    Posts
    311
    remember not to let the unibit get too hot. I just used a 1 3/8" unibit to cut a 1" hole in seven peices of 1/2" steel for a rock rake for my tractor. The last hole was a bear to cut because I did not wait for the bit to cool between holes. But it worked quickly and did not have to use several drill bits.
    EPILOG LEGEND 32 60 WATT, CORELDRAWX5, PhotoGraV2.11, strip heater, PUNTA GORDA, FLORIDA

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