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Thread: Drill and Tap suggestions

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  1. #1
    Join Date
    Mar 2003
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    Arizona
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    Default Drill and Tap suggestions

    I want to drill and tap a symmetrical pattern (like a grid) of 1/2" x 13 TPI holes in one of my 4'-0" x 4'-0" x 1/2" thick fab-tables. Using them for my mill hold down clamps. I've drilled and tapped before so that's not the issue in the slightest. I'm trying to figure out the best way to accomplish it. I was thinking of renting a magnetic drill press. Never used one and I haven't called to see what the rental price might be yet. Naturally I'd like to accomplish this without renting anythings. Just thought someone might have an idea. Never hurts to ask ya know.

    -SD:

  2. #2
    Join Date
    Sep 2015
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    NW Illinois
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    If the fab tables are already built the mag base drill is likely the only practical way to do it.

  3. #3
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    Quote Originally Posted by Illinoyance View Post
    If the fab tables are already built the mag base drill is likely the only practical way to do it.
    Thanks, the fab-table is already built. I only need to do one.

  4. #4
    Join Date
    Jun 2011
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    Northeast, PA
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    Mag drill would be easier but you might get away with a small benchtop drill press if you swing the head away from the base. C clamp it down at the edge and then use the drilled and tapped holes as you go for hold down clamps.

  5. #5
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    San Jose, CA:Vancouver, WA
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    We bought a mag drill just to drill ~40 1" holes in 1" steel. Worth the investment (~$1500) to do the job. You find more uses for it.

    Layout the hole pattern and use a center finder to locate each hole carefully and you will be happy with the results.

    Mike

  6. #6
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    Sep 2015
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    NW Illinois
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    For one table top just rent a mag drill. If equipped with a chuck you can tap with it also.

  7. #7
    Join Date
    Oct 2002
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    Kirkland, Washington
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    Default

    Quote Originally Posted by MikeL46 View Post
    We bought a mag drill just to drill ~40 1" holes in 1" steel. Worth the investment (~$1500) to do the job. You find more uses for it.

    Layout the hole pattern and use a center finder to locate each hole carefully and you will be happy with the results.

    Mike
    Common practice on mag drills is to lay out your holes and centerpunch them. For each hole, install a tapered pin in the spindle. Lower the pin with the magnet off, feeling for the hole. When you feel the pin catch the centerpunched hole, turn on the magnet, install your bit and drill. No need for a center finder.

    If $100 is too much for the use of a mag drill, carefully buy a mag drill (used), use it, and resell it. If you are careful about pricing, you can often achieve "free rent" this way.

    metalmagpie
    Last edited by metalmagpie; 07-05-2019 at 05:06 PM.

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