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Thread: Advice on drilling into a bolt carrier

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    Advice on drilling into a bolt carrier

    From reading, they appear to have an hrc of around 50-55. Using a regular drill press, what advice can y'all give on what bit / jogger to drill and tap? Any recommended taps suitable for such a hardened steel?

    Thank you.

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    If you have to ask, you probably shouldnít. Sorry but as a machinist cutting something that hard is a pain even with carbide tooling and solid workholding. Itís not something I would want to do with a drill press and hobby tooling.

    The good news, if you decide to go ahead. Carriers are only surface hardened. If you have a carbide spot that can break through, you should be able to use a regular drill and tap. Go slow, use lots of oil.

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    What exactly are you drilling and tapping? Did you break off a gas key fastener?

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    Quote Originally Posted by DoubleW View Post
    What exactly are you drilling and tapping? Did you break off a gas key fastener?
    Sometimes you just need a hole in a carrier, man!
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

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    Now Iím thinking heís building some type of side charger

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    Quote Originally Posted by DoubleW View Post
    Now I’m thinking he’s building some type of side charger
    In that case, this thread would need to be transferred to ARFcom!
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

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    Quote Originally Posted by markm View Post
    In that case, this thread would need to be transferred to ARFcom!
    True story. When I was in the process of researching my first can I reached out to Otter Creek and asked about their warranty policy. The response was "We will fix any damaged can no matter what. Unless you do something REALLY stupid like take a hand drill and try and make a 30 cal can out of a 5.56 can." I said that is far too specific for you to have made that up. He said, "it's happened. We charged him $200 for being dumb." LMFAO. The thought process around that event is the ultimate Bubba.

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    Quote Originally Posted by Dutch110 View Post
    True story. When I was in the process of researching my first can I reached out to Otter Creek and asked about their warranty policy. The response was "We will fix any damaged can no matter what. Unless you do something REALLY stupid like take a hand drill and try and make a 30 cal can out of a 5.56 can." I said that is far too specific for you to have made that up. He said, "it's happened. We charged him $200 for being dumb." LMFAO. The thought process around that event is the ultimate Bubba.
    That's called the stupid tax, lol

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    Quote Originally Posted by Austin26 View Post
    From reading, they appear to have an hrc of around 50-55. Using a regular drill press, what advice can y'all give on what bit / jogger to drill and tap? Any recommended taps suitable for such a hardened steel?

    Thank you.
    Will try and help answer, vs knocking your question.
    Asking questions is for doers. Can't become a doer without asking questions.

    You said BCG, so I will assume through hole.
    In the realm of C158 or 9310, cobalt drill bits will work.
    Setup and cooling is also key. I prefer a flow of cutting fluid to cool and remove chips.
    Holding the piece tight in correct geometry is imperative, so it needs correct vice and maybe a mounting jig of some kind, what that jig is varies.
    Spotting the location is a good 1st step, a carbide spotting bit is ok here.
    For a through hole, and depending on size, but lets say 1/4", I would perhaps start with 1/8" then finish off with 1/4" piloted cobalt.
    Must use drill size specified by the tap being used.
    All that said, it assumes a decent press with tight quill bearings.

    So in general, good setup, cutting/cooling fluid, correct bits and procedure, and slow speed with medium'ish pressure.

    As for tapping, it's a slow procedure. If you can find an undersized tap, that would be best. Grainger or McMaster for those. Cutting oil and very short turns by hand, 1/8th turns would probably be pushing the limits by hand. Cut a little, back out some, every 1/4 turn (90deg) worth of cut, back it all out, clean it all, go again.
    Again, it's a very slow process.

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    Quote Originally Posted by DwayneZ View Post
    Will try and help answer, vs knocking your question.
    Asking questions is for doers. Can't become a doer without asking questions.

    You said BCG, so I will assume through hole.
    In the realm of C158 or 9310, cobalt drill bits will work.
    Setup and cooling is also key. I prefer a flow of cutting fluid to cool and remove chips.
    Holding the piece tight in correct geometry is imperative, so it needs correct vice and maybe a mounting jig of some kind, what that jig is varies.
    Spotting the location is a good 1st step, a carbide spotting bit is ok here.
    For a through hole, and depending on size, but lets say 1/4", I would perhaps start with 1/8" then finish off with 1/4" piloted cobalt.
    Must use drill size specified by the tap being used.
    All that said, it assumes a decent press with tight quill bearings.

    So in general, good setup, cutting/cooling fluid, correct bits and procedure, and slow speed with medium'ish pressure.

    As for tapping, it's a slow procedure. If you can find an undersized tap, that would be best. Grainger or McMaster for those. Cutting oil and very short turns by hand, 1/8th turns would probably be pushing the limits by hand. Cut a little, back out some, every 1/4 turn (90deg) worth of cut, back it all out, clean it all, go again.
    Again, it's a very slow process.
    I asked what exactly he was drilling and he never responded, so not exactly knocking anything. There is absolutely zero reason to drill into a carrier. Zero. The only possible reason would be if a fastener broke off and had to be drilled out. Thereís no need to encourage and educate someone on how to compromise the integrity of a critical firearm component by doing doing something ignorant.

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