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  1. #1
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    Precision Holes - How do you guys make them?

    Just out of curiosity, how do you guys make precision - very clean exact holes? The only holes I need to be very precise are those where I am going to put my lens. Currently I am getting help but eventually I would like to make my own.

    What makes it particularly hard is the fact the hole I need to make for the front is a bit bigger than 3/4"(20mm)

    How do you guys make even bigger holes for you optics and such?

  2. #2
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    Since you didn't say anything about how much the equipment costs....I use my mill either with the rotary table or under CNC control. Makes very nice clean holes of any size.

    If your question is how to make them fairly inexpensively, that's actually kinda hard. Your best bet would probably be with a cheap benchtop drill press with a bimetal hole saw. If you're doing this in thin metal, such as the front of a project box, you'll need to put a block of wood behind the piece of metal to support it. If you're pretty careful and with some practice you should be able to get reasonable holes. You may need to clean then up with a file a little. I don't think you'll have much luck using a hole saw with a handheld drill, you really need the stability of a drill press.

    If you have to make a lot of one particular size, then a knockout-punch is a good option.
    http://www.mcmaster.com/#knockout-punches/=8jles9

  3. #3
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    For years the only holes I could drill were egg shaped and in the wrong place but after years of practice and mistakes I can now get them spot on.

    great tips from MtbMacgyver but a few others are to make sure that your tools are sharp, use a good centre punch berore you start, followed by a centre drill.

    You don't say how you will be making holes but a boring bar on a lathe works good for me, with a four jaw chuck if you are working on a square object.

    This is a vid of my madness and I hope that it helps:
    EDIT: fujio I have just read your other thread. If you are drilling or cutting lower grade soft aluminium then use a slow speed and lots of oil to keep it cool as it would rather melt than cut.
    Last edited by yetibetty; 08-24-2010 at 07:25 PM.

  4. #4
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    I was hoping to use hand tools but is sounds like that would be quite difficult. Now what does sound very interesting is the knock-out punch. How clean of a hole do these things make?

    With a 3/4"(around 19mm) punch, a reamer could slightly expand the hole to 20mm. Nice opening for a 20mm lens(actually I would put a flashlight lens and then place the LED/optic behind it.

  5. #5
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    Hi, Fujio have you tried using a step drill bit?

  6. #6
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    For thin front or back plates...back it up with a wood block, center punch and drill it with a step drill. You will have to hold it with a vise or c-clamps.

    Edit...Dang, I type slow.

  7. #7
    1*14*29*2.1 & 1*1*29*2.4
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    I haven't tried this with big holes, but if you can find a tapered reamer with a large diameter that can be an easy way to neaten up a bad hole, as long as you don't take off so much the hole isn't the right size anymore.

    http://www2.blackwoods.com.au/infoBA...4474&P=7119910

  8. #8
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    I have heard of step drill bits and I do have access to a tapered reamer.

    Used in conjunction the step drill bit may work well with just a simple hand held drill!

  9. #9
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    With softer non-heat treated aluminum, will a knockout punch have a tendency to bend or deform the piece of aluminum you are trying to cut?

    The 3/4" hole I am tying to cut is in he center of a softer aluminum 2.5" x 1.2" piece.

  10. #10
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    I have only use it a few times but the step drill bit worked well for me as long as the material is not too thick. As previous posters have mentioned, you need to have a solid back block and clamp it down well.

  11. #11
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    I drilled the holes for the bolts on the end of these lights i made, with a hand drill..

  12. #12
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    Quote Originally Posted by Goldigger
    I drilled the holes for the bolts on the end of these lights i made, with a hand drill..
    That's impressive for hand drilling. If you have a description of your procedure, the OP and others may find it useful.

  13. #13
    1*14*29*2.1 & 1*1*29*2.4
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    small holes aren't normaly a problem though?

  14. #14
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    I always use a mill and an end mill bit of the size hole required or my lathe. However for accurate larger holes by hand I usually drill a pilot hole no more that 25% the size off the hole required then drill the correct size hole after that. Make sure you use plenty of lubricant and ensure that the drill is sharp with both cutting edges of the bit the same length and angle. If one is longer than the other the drill will pull to one side and you will end up with an oversized hole.

    One cutter that can be very good is a carbide tipped hole saw. They cut very accurate holes if you use the style shown in this link http://www.desertelectric.com/ideal_tko.aspx

  15. #15
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    double response

  16. #16
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    I didn't really have a procedure, I just marked out the holes and drilled them..just making sure to keep the drill straight as possible.
    I did however snap about 5 drill bits as they were only 1.5 or 2mm..
    You can get an attachment that turns a hand drill into a cheap bench drill, its a cheap way to drill straight accurate holes.
    http://findingking.net/Bench-Drill-P...ource=GB&id=uk
    Last edited by Goldigger; 08-28-2010 at 01:36 AM.

  17. #17
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    I have managed to precisely drill by hand by using a center punch, centering drill bit (I think that's what it's called) and then slowly increasing the drill size.
    We can bomb the world to pieces, but we can't bomb it into peace -Michael Franti

  18. #18
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    Step Bit

    I use a drill press for accuracy, but for a good clean hole, if you don't have access to a mill, I think that the Stepped Drill bits give a really clean hole.

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