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Thread: Difference between Cobalt and Carbide drill bits?

  1. #1
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    Difference between Cobalt and Carbide drill bits?


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    Can someone explain the usability difference between Cobalt and Carbide drill bits?

    Thanks,

    Dave

  2. #2
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    Carbide bits can be used to drill already hardened steel. But they are brittle and tend to break if you're not real careful.

    Cobalt bits are the greatest for drilling annealed ready to work steel. They will outlast high speed steel bits four to one so they are worth the little bit extra they cost.

    Hope this helps.

  3. #3
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    cobalt and silicon carbide drill bits

    Well it may not be much but here is a start for you. Cobalt is often added to "regular steel drilling" bits. It does improve cutting abilty considerably. The common amount of cobalt added is usually 8%. Silicon carbide can be a great cutter but is very brittle and is used in bits to drill very hard steels and also in masonary bits. The silicon carbibe bits are usually at least twice or more the cost of regular bits. Lots of care and good cutting fluids with reduced drilling speeds should be used with a reasonable, and controlled amount of pressure. Silicon carbibe drill bits in "true" fractional and numbered sizes also not commonly available. However, properly used in the applications necessary silicon carbide bits will drill very accurate holes. Frank Niro

  4. #4
    I have used Cobalt bits for drilling 1084 ang 1095. I works fine as long as you use good cutting oil and make sure you don't drill too fast or it will dull the bit and make it really hard to drill anything with it.

  5. #5
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    Re: cobalt and silicon carbide drill bits

    Originally posted by Frank Niro
    Well it may not be much but here is a start for you. Cobalt is often added to "regular steel drilling" bits. It does improve cutting abilty considerably. The common amount of cobalt added is usually 8%. Silicon carbide can be a great cutter but is very brittle and is used in bits to drill very hard steels and also in masonary bits. The silicon carbibe bits are usually at least twice or more the cost of regular bits. Lots of care and good cutting fluids with reduced drilling speeds should be used with a reasonable, and controlled amount of pressure. Silicon carbibe drill bits in "true" fractional and numbered sizes also not commonly available. However, properly used in the applications necessary silicon carbide bits will drill very accurate holes. Frank Niro
    Never heard of a Silicon Carbide drill bit, and I regrind machine tools on a regular basis!!

    Carbide drill bits, end mills, ect. are all Tungsten Carbide, with a Cobalt binder (W, C, & CO), and are generally whats available.

    Silicon Carbide is used in grinding wheels (green wheels), and in some grinding belts.

    Other than clarifying the make-up of carbide tools, the rest is right on.

  6. #6
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    And what about

    Titanium carbide or nitride coated bits vs cobalt bits?

  7. #7
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    Illinois, USA
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    IMO...

    ...the cobalt bits are about the best for general knifemaking work. They work well and stay sharper longer on just about any kind of steel I drill.

    The titanium nitrite, high speed steel and such are, to me anyway, pretty much just cobalt wanna bees. They are ok for thin easy to drill stuff but for lasting sharpness and acurate hole drilling use the cobalt.

    A good drill bit sharpener and a cobalt bit will make any drilling job easier.



    Brian

  8. You might want to check out tungsten carbide, which can keep its sharp edges for a longer period of time:

    Tungsten carbide is a type of steel mainly comprising of cobalt as well as tungsten carbide. The cobalt will act as a binder and help enhance shock resistance when drilling. The shock resistance provided will depend on the percentage of cobalt used to manufacture the product, and usually a small amount of wax will be added to hold the materials together. Tungsten carbide is a high-strength material and has a compression strength greater than many forged metals and alloys. This type of steel has a tensile strength ranging from 100,000 to 500,000 PSI.
    source: http://carbidedrillhq.com

  9. #9
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    ticker web on cobalt bits might not be ideal in certain situations compared to hss. cobalt bits are m35 & m42: 5 & 8% co respectively.

  10. #10
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    Holy thread resurrection batman!
    Now that I have seen, I am responsible. Faith without deeds is dead.

    Hunter Martin
    The Huntsman Knife Company

  11. #11
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    Oh my god... this thread... so much fail...


    "Build a man a fire and he'll be warm for a night. Set a man on fire and he'll be warm the rest of his life"

    KMG flat platens, radius platens and water cooled chillers: http://www.bladeforums.com/forums/sh...ad.php/1222480

  12. #12
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    12 plus year resurrect. Holy cow.

  13. #13
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    I see no reason why any sane person would want to drill steel post-HT.

  14. #14
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    Nov 2003
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    Chemistguy, are knifemakers sane?
    Perhaps some one forgot to drill all the holes prior to heat treat?
    That has never happened to anyone on this board, I'm sure. LOL
    Fred

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