If you are drilling a concrete wall

Well, this is definitely something that is very relevant to Taiwan as 9 times out of ten if you need to install something, like drapes, blinds, or curtains, you have to drill into concrete.

Well basically it seems when drilling concrete the drilling seems to be SLOW as hell and hole seems to want to move on you? I got a tip…

The bit is dull, or rather I think most masonry bit they sell is dull out of the box. So it won’t cut properly. I found this out because I was installing bathroom fixtures and I tried sharpening the bit, and it made a big difference. Not only the hole drilled much faster, but it also didn’t walk around and the hole was cleaner, so the insert didn’t slip around.

Now the problem is you need diamond wheels to sharpen masonry bit because they are carbide tipped… but if you got a Dremel you can use a diamond wheel to sharpen it, it will improve the bit a LOT. At least as much as it would on a standard hammer drill… if you want to drill large holes you should use a rotary hammer that takes SDS bits…

Personally I always drill a small pilot hole in concrete. It’s not foolproof, but it usually ends up with the hole in the right place +/-1mm.

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It’s kinda hard to drill a pilot hole because the smallest masonry bit they have is 3mm in diameter. And for most mounting needs that’s about what you’d use.

yeah, 3 or 4mm works for me. Maybe my drill bit supplier is better than yours :wink:

Generally I find myself drilling 6-8mm holes for shelves and whatnot.

I was wondering who it was who did all that drilling.

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For stone and concrete it’s much better to use the hammer drill settings, masonry drill bits are designed to chip out the material rather than cut it. Think of the wings at the head of the drill bit as a small jackhammer. Also if the surface is smooth I will put a cross with masking tape to help prevent it slipping.

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Hammer drill on hammer setting cuts through concrete inner walls like butter. Exterior walls can be slower going but the hammer drill handles it.

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If the bit is dull, it won’t cut well and will walk all over you regardless of setting…

If its dull, it’s old or a cheep bit. They are not supper sharp anyway as they are more like a bolster chisel, that’s why you need the hammer setting. You shouldn’t need to sharpen a bit unless it’s been used a good few times (or it’s been used on a drill without hammer setting which will kill it very quickly).

You don’t see trades people sharpening a new bit every time they put one in, watch workmen putting in window frames or fixings to a building they will drill dozens of holes in concrete without changing the bit.

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I use the hammer setting when drilling concrete. Especially those plug in hammer drills that are really shit. Right now I have a cordless drill that also have the hammer function and it is very useful for all kinds of work.

You can sharpen them on a standard bench grinder or even by hand with a file, don’t need anything fancier.

I would suggest using a hammer chisel. Find the chisel the best size for the hole you need. Then drill. Then hammer in your anchor. My applications were hanging things overhead - channels for hanging curtains and sound panels. Are strong enough you can use for pullups.

You can’t sharpen masonry bits with a file or even a bench grinder. Carbide is actually harder than the stones bench grinder is made of and it won’t even scratch it. All it will do is dress the stone. You need silicon carbide grinding stones or diamond to grind it. Forget about files, it won’t even scratch a standard drill bit which is made of high speed steel.

Silicon carbide stone is generally green.

LOL, your glass is always half empty. Have you ever tried?

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I tried to grind carbide with standard grinding wheels. Apart from buffing the carbide, it makes no dent to it whatsoever.

You can buy Dimond file for a couple of hundred NT just takes a bit of time. If your having problems after one hole, i don’t think your tip is as hard as you think it is. :innocent:

We use a mix of chemical and mechanical anchors (but probably on a bigger scale) we normally stick to Hilti due to insurance.

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Yes, these drop-in anchors are what I love to use. Super strong.

Well… If you have a higher power hammer drill, it’s fine for occasional use. Larger holes / lots of holes / low power drill is just an exercise in frustration when dealing with concrete and masonry. Practically every time I have to drill concrete I find myself thinking about buying a rotary hammer, and I have a big boy DeWalt 999 hammer drill.

I have a Makita cordless drill with hammer setting. It isn’t that powerful as far as hammer goes but it handles a lot nicer and quieter than those large hammer drills. I feel anything bigger and you should buy a rotary hammer. I saw it on clearance at B&Q for around 2000.