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Please excuse my ignorance, I'm fairly new to DIY.

I keep reading how masonry drill bits wear down quickly. As I'm preparing for a day of serious hammer drilling dozens of holes into concrete walls at a remote location, I'm wondering how many drill bits I need to bring. How many holes can a single masonry drill bit realistically be expected to make before needing replacement?

I have searched the web and YouTube for all kinds of phrases and terms, but can't seem to find any quality assessments the same way as for example screwdriver bits are often tested.

I realize the answer relies heavily on the quality of the bit, proper usage, etc. But I really have no idea right now. I'm intending to buy Irwin SpeedHammer bits, which I believe are a reasonable quality. I will try to prevent bits from getting too hot.

Should I expect 10 holes? 100? 1000?

Any guidance would be appreciated.

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    Since you are going to be remote, having spares is important.. You should buy brand new spare bits from a major big box store and leave them in the package. Any left overs can be returned for full credit (store or back onto your credit card) VERY easily. I can't answer the longevity part of the question as I've only ever used my masonry bit a handful of times. Even if one should last, it may be worthwhile to have a couple of spares. Just in case. – UnhandledExcepSean Aug 29 '16 at 16:56
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    How many holes can one bit drill? Depends entirely on the quality of the bit and the material being drilled (including obstacles hidden in the concrete such as metal). I agree with @Ghost, overbuy and return what's not needed. – Tyson Aug 29 '16 at 17:12
  • I've never had any trouble returning items to my local family owned lumberyard/ building supply, which saves me the trouble of doing business with the nasty big box stores and helps me support local businesses. – Harper Aug 29 '16 at 18:18
  • Thanks for the suggestions. Returning unused items is not an option where I am, in Thailand. The vast majority of vendors don't accept returns here. – Rob de Jonge Aug 29 '16 at 18:26
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    I am planning to take at least twice as many as I need, 3x as many if I only need 1-2. Just in case. But I don't know how many I need, hence the question 😄 – Rob de Jonge Aug 29 '16 at 18:42
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I can't give an exhaustive scientific answer, but I have plenty of hammerdrilling experience, both with SDS bits and smooth shank bits. I have a Bosch Bulldog and seeing that you'll be drilling for hours into concrete, would strongly encourage you to be using this or some other SDS handling tool:

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It depends on the diameter of your bit and how deep each hole is - I have drilled hundreds of holes with my half inch SDS bit without any sign of weakening (though moderate wear on the tip is apparent). But whether SDS or smooth shank, a 3/16" bit such as is used for drilling for 1/4" masonry lags can be expected to drill, oh, my best guess is maybe 200 3-inch holes before becoming significantly dull (breaking is almost always user error). This is assuming concrete without foreign objects.

Perhaps due to your remote location, you are stuck with a non-SDS battery hammerdrill. Those Irwin bits should work okay in that case, just at least twice as slow as the SDS system (which is why I would really encourage you to get your hands on the SDS drill).

In the final analysis, I would calculate one bit per hundred holes if you're using 3/16" bits. You will probably break some.

  • Great answer and a number to work with. You're right, using a DeWalt battery hammer drill. No SDS possible. Plenty of batteries, although my arm will probably wear out! Thanks so much, very helpful. – Rob de Jonge Aug 31 '16 at 8:13

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