How to make rectangular holes in diy PCB?

Discussion in 'General Electronics Chat' started by Ωhm, Mar 24, 2012.

  1. Ωhm

    Thread Starter New Member

    Feb 1, 2012
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    Just curious if anyone knows of any punches/saws that can be used to create nice, smooth edged, professional looking slots in PCBs for components like switches or potentiometers that frequently come with flat/bladed leads as opposed to round leads.

    I suppose one could drill a circular hole large enough to accommodate the dimensions of a flat/bladed lead but that is sloppy and requires a lot of solder fill. I've seen hand punches with squeeze handles but those are obviously limited to the throat depth of the tool which may or may not reach the required location on the board.

    Would love to hear how people have handled this issue when doing their own boards. Thanks,
    Ωhm.
     
    Last edited: Mar 24, 2012
  2. nerdegutta

    Moderator

    Dec 15, 2009
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    You can drill a small hole in the middle, and use this kind of saw to cut your square.
    [​IMG]

    Or you can use a Dremel, with a cutting blade.
     
  3. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Last edited: Mar 24, 2012
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    @atferrari- those only work in metal. They have been around a long time, under a different name. The company I server my apprenticeship for look at buying them back in the late 1960s. They can do many different shapes, each shape has a separate "holder" that goes in the machine spindle, that allows the cutter to move in the correct pattern for that shape. http://www.maa.org/mathtourist/mathtourist_08_31_09.html
     
  5. IanFiTheDwarf

    New Member

    Mar 8, 2011
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    What you need is a broach, first drill a round hole then push the broach threw the hole to change the shape.

    The broach will be round at the bottom, the shape you require at the top and will gradually change from round to the required shape in steps along its length with each step being a little cutter.

    I have made a broach for making a keyway before but



    http://fiveelements.in/dominoes-isuzu-bighorn-removal-of-keyway/


    round to square at the top right of the page


    http://www.modelsforsale.com/catalo...ch-Set-0.6---2.0mm-Scale-0.6---2.0mm-#PBR2194



     
  6. ErnieM

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    Apr 24, 2011
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    For low volume work (single piece items) I have used a nibbling tool:

    [​IMG]

    It is slow and takes a lot of effort to remove small pieces, and you'll probably come back to dress it with a file, but it gets the job done.
     
  7. atferrari

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    Why not in a PCB?
     
  8. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    It needs the metal to give resistance to the cutting bit, to make it follow the mechanism in the "driver"(the part that goes in the machine spindle). Each size hole you make has a different size cutting bit.
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    I just don't use parts that have flat leads. Most switches and pots these days are available in "PCB" style which usually means they have round leads to go in PCBs. The ones with thick flat terminals are for flylead soldering, not PCB mounting.
     
  10. Ωhm

    Thread Starter New Member

    Feb 1, 2012
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    Thanks for the ideas guys. I've been buried in work so I am just getting around to responding. You've given me some good food for thought. All my junk box switches are the bladed type so I will have to make do and get inventive.
     
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