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The cutting end of a bit meant for a hammer drill looks quite similar to an ordinary masonry bit. The tungsten carbide insert may be a bit thicker. |
A long bit like this is good for drilling through 8 inch (200mm) cinderblock walls. |
Long SDS masonry bit. |
Very long SDS masonry bit. |
Masonry bits tend to be longer than bits meant for steel, because a lot of people have 8-inch (200mm) thick concrete, brick, or cinderblock walls, but very few people have 8-inch thick steel walls. |
Long masonry bit. |
Drilling through glass or fine-grained porcelain calls for a tungsten carbide spear-point drill. They come in two-flute and four-flute varieties. |
These bits are optimized for cutting glass or fine-grained porcelain. |
Masonry bits come with widely different styles of flutes. |
Masonry bits rely on a chunk of extremely hard tungsten carbide brazed to the tip of a steel shank. |
Carbide Glass Drills |
4-flute glass cutting bit |
This expensive tungsten carbide bit is designed to cut through concrete with embedded reinforcing bars (typically ½” - ¾”, 12-18mm, thick steel). For steel you want a sharp bit, for concrete you want a blunt bit, so this is a tough combination to get through. |
I got these ordinarily very expensive carbide-tipped hole saws at an auction. This was fortunate because shortly thereafter I needed to drill a sizable hole through the very hard bricks on my house. |
Every home should have a few of these masonry bits. |
Masonry Bits |
Even though concrete is very hard, drilling it actually takes less force than cutting steel, because you can chip away at it a bit at a time. A huge bit like this can be driven by a small, handheld electric drill (note the small diameter shank). |
This is the core left after drilling a hole through a brick on my house using a carbide-tipped hole saw. |
Long masonry bits. |
Do you have a better example of this kind of tool? Let me know by leaving a comment, and include a picture of it if you can so everyone can see!