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I was hanging some shelves on my kitchen walls. It's an interior wall of a 100 year old addition, these seem to be drywall glued directly to red brick, maybe plaster with dry wall glued to it. I didn't trust plastic anchors because of the weight and the unknown stability of the drywall, so I used Tapcon screws to reach through the half inch of drywall and get into the brick.

Seemed easy, but I had a serious problem with masonry bits. I was using a 7.5A Skil hammerdrill and only 5/32 holes, but the carbide tips broke off in 3 of 9 holes. First was a well used Dewalt bit with hammer turned on, then a brand new Mastercraft bit which i used slower without hammer (didn't last 1 hole), and then I was down to no-name wobbly bits included for free with various tools over the years. I don't think they did any worse, I had to treat them like gold (slower drilling, no hammering, pausing, blowing on the bit it to cool it), still broke one, but these cheap things got me through the job.

Anyone know why carbide bits would fail like this? Never had this happen before, but I don't do a lot of this. The biggest pain is that after it breaks, now you've got a hole with a carbide lost under a half inch of brick inside it... how can you even get it out?

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    Normal drills spin to scrape material off the surface. Works on wood and metal. Does not work at all on masonry, which is far too hard, abrasive and brittle for that. Masonry holes are "drilled" via impact and shattering of the target stone.
    – Harper - Reinstate Monica
    Commented Jun 6, 2021 at 6:27
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    This. Why on earth are you using masonry drill bits without hammer, anyway? They pretty much won't do a thing except slow limited holes and get blunt then.
    – Stilez
    Commented Jun 6, 2021 at 8:47
  • because the first bit broke under hammer
    – mgjk
    Commented Jun 6, 2021 at 12:11
  • My experience is that without hammer you're fine on softer concrete, mortar etc. It's not like I've never drilled a hole before, and I've drilled plenty of holes in masonry without a hammerdrill, it's slow as hell and takes patience. Never broke a bit like this.
    – mgjk
    Commented Jun 6, 2021 at 12:16
  • Yes. In soft (aerated) concrete and weak mortar, you could get away with a cheap wood drill bit and no hammer. But this sounds like a non-weak wall, though.
    – Stilez
    Commented Jun 6, 2021 at 17:33

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I would say without hammer you will be heating the carbide more although it can usually last running without hammer in mortar it usually takes longer, hitting a steel reenforcement is a reason for breaking carbide tips sure it happens but drilling brick and mortar is normally fairly easy so you may have hit metal and that broke the first bit then overheated the other bits would be my guess. Is it possible to get the carbide out? When I have hit metal and broke a bit it is usually just a piece of carbide left in the hole I will go old school with a punch and hammer, strike rotate punch strike, it takes experience but you can feel the difference of concrete or brick and mortar compared to steel the bounce back of the punch is “sharp feeling” or more fo a kick back and I have hit a few pieces of rebar, structural steel and even angle iron in some walls that I was not sure why it was there. So that could be what broke the original bit.

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    Water helps a lot to cool bit and wash out debris.
    – blacksmith37
    Commented Jun 6, 2021 at 18:32
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    never considered metal in the wall, thanks. The house is 100+ years old, so it's really hard to know what this wall is made of. The only clue is it's solid, and red powder comes out when after you get through the drywall or plaster. I'll have a close look at the wall from the basement, might be more clues.
    – mgjk
    Commented Jun 6, 2021 at 18:59
  • Red powder sounds like brick, but as I mentioned I have found steel reinforcements.
    – Ed Beal
    Commented Jun 7, 2021 at 0:11

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