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  1. #1
    Join Date
    May 2011
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    Default Sharpening a Centre Punch

    To get a nice consistent point on my Centre Punches, I put them in the DP at around 600 rpm, and use a small angle grinder held at the correct angle, for a short period.
    Taking off the mushroom head can also be done on the DP, with good results.
    Kryn
    To grow old is mandatory, growing up is optional.

  2. #2
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    Oct 2010
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    melbourne, laverton
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    Default

    Cool Merrill try that

  3. #3
    BobL is offline Member: Blue and white apron brigade
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    Default

    Both my spring loaded centre punches won't run true in my drill press, while the non-spring loaded ones have square shanks

  4. #4
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    Sep 2012
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    Default

    Quote Originally Posted by BobL View Post
    Both my spring loaded centre punches won't run true in my drill press, while the non-spring loaded ones have square shanks
    Hi Bob, Guys,

    The spring loaded ones, I remove the punch, its also easy to make new ones for them !

    I sharpen my centre punches in the lathe using a Dremel in the tool post. About the only time that I've used the drill press is to hold a short length of silver steel when I've already made the point by turning and I'm heating it to harden the tip. I spin the silver steel and then get it red with a cooks torch, then plunge into a tin of oil ! Usually the cooking oil that the wife throws out of the chip pan, smells of chips... mmm. I've made several transfer punches this way.
    Best Regards:
    Baron J.

  5. #5
    BobL is offline Member: Blue and white apron brigade
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    Default

    Useful tip about removing the tip on a spring loaded punch to sharpen it.

    To sharpen tips on stuff that fits in a cordless drill I spin the tips against an unsupported part of a Linisher belt.
    Sometimes I sharpen TIG tips against a diamond wheel.
    The tips on the tines of this wool carding comb were made this way.
    The tines are pieces of TIG rod

    IMG_4685.jpg
    Which is why I wanted to get the all the same length.
    colletEnd.JPG
    Attached Images Attached Images

  6. #6
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    Oct 2004
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    Southern Highlands NSW
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    Default

    Note that grinding should be parallel to the axis of the punch, not across it.

  7. #7
    Join Date
    Nov 2007
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    melbourne australia
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    Default

    Quote Originally Posted by nadroj View Post
    Note that grinding should be parallel to the axis of the punch, not across it.
    I can’t picture what that means. And even if I could, I don’t think I’d understand why. Can you elaborate please Jordan?
    Chris

  8. #8
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    Nov 2008
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    North Brisbane. Qld. Australia
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    Quote Originally Posted by jack620 View Post
    I can’t picture what that means. And even if I could, I don’t think I’d understand why. Can you elaborate please Jordan?
    Grinding along shank toward tip I assume. Didn't know that 'till now. Thanks.
    Nev.

  9. #9
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by nadroj View Post
    Note that grinding should be parallel to the axis of the punch, not across it.
    I grind/shape across a coarser belt first, and if possible also use an unsupported part of the belt to avoid getting a flat. Then switch to a finer belt along the line of the work

  10. #10
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    Oct 2004
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    I read it in a few different places, that grinding a centre punch should be such that any grooves (tiny but there) should be towards the conical tip.
    I thinks it's to minimise the effect of any stress risers weakening the tip.

  11. #11
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    Sep 2012
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    York, North Yorkshire UK
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    Hi Guys,

    I have a centre punch that does not have a conical point !

    Instead it has a three sided pyramid shaped point and is quite sharp compared to the conical point ones. Its also very easy to find the intersection of scribed lines with it. You can easily feel the scribe mark.
    Best Regards:
    Baron J.

  12. #12
    Join Date
    Mar 2013
    Location
    Mt Pleasant SA
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    126

    Default

    Quote Originally Posted by BaronJ View Post
    Hi Guys,

    I have a centre punch that does not have a conical point !

    Instead it has a three sided pyramid shaped point and is quite sharp compared to the conical point ones. Its also very easy to find the intersection of scribed lines with it. You can easily feel the scribe mark.
    Meant for centre punching stainless steel .. as are 4 sided. Theory is it's easier for the drill point to cut thro' the work hardening.

  13. #13
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    May 2020
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    s.w. sydney
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    Default

    Quote Originally Posted by KBs PensNmore View Post
    To get a nice consistent point on my Centre Punches
    Kryn
    just curious, why does it need to be a nice consistent point ?
    i sharpen drills 3mm to 60mm on a bench grinder, whats wrong with a bench grinder?
    cheers

  14. #14
    Join Date
    Aug 2008
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    Melbourne
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    Default

    You want to make it consistent so it's easier to line up on your scribe lines. Nothing wrong with a bench grinder at all
    Gear cutting specialists and general engineers www.hardmanbros.com.au
    Fine pitch gear cutting from 0.1 Module www.rigear.com.au

  15. #15
    Join Date
    May 2020
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    s.w. sydney
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    Default

    Quote Originally Posted by elanjacobs View Post
    You want to make it consistent so it's easier to line up on your scribe lines. Nothing wrong with a bench grinder at all
    i think i understand, i would call it a "fine" point

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