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Thread: Difference between Cobalt and Carbide drill bits?

  1. #1
    Join Date
    May 1999
    Location
    Tenino, WA [between Yelm and Bucoda]
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    614

    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
    Join Date
    Apr 1999
    Location
    Wichita, Kansas
    Posts
    170
    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
    Join Date
    Sep 2000
    Location
    Kamloops B.C. Canada
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    2,938

    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
    Join Date
    Jul 2000
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    S.E. Washington State
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    9,684

    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
    Join Date
    Nov 2001
    Location
    Milano, Italy
    Posts
    1,375

    And what about

    Titanium carbide or nitride coated bits vs cobalt bits?

  7. #7
    Join Date
    Mar 2001
    Location
    Illinois, USA
    Posts
    138

    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

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