5 ms·

Haha. I have a cordless brushless impact driver. First time I used it to put a screw in a wall it went in so fast I didn't stop in time and it stripped the head

by fy20 5y ago

Haha. I have a cordless brushless impact driver. First time I used it to put a screw in a wall it went in so fast I didn't stop in time and it stripped the head :D

sam_lowry_ 5y ago
Cordless impact drivers or even 230V ones like Bosch Advanced Impact do not perform well on reinforced concrete. You need a pneumatic hammer drill. Visually they are quite different because of the SDS head.
- jessaustin 5y ago
  Lots of perfectly functional SDS hammer drills are electric (here in USA they're 120V). This is different from what I've called an impact driver, which is more for turning fasteners than drilling holes. Even Harbor Freight sells a few electric hammer drills that will sink smaller diameters like 1/4" at about 2 seconds per inch. Larger diameter bits take longer, but there's no need for an air compressor. I'm not sure why you'd mention "reinforced" concrete. I thought all concrete required reinforcement of some sort? Fiber won't be an issue, but if you hit rebar it's time to relocate your hole, no matter what you're drilling with. Even if the drill can do it you're going to ruin the bit.
  - bayindirh 5y ago
    > I'm not sure why you'd mention "reinforced" concrete. I thought all concrete required reinforcement of some sort? Concrete can be tuned for brittleness and strength. Some versions become very hard and impenetrable after they completely cure. They need more powerful drills and longer drill times since they simply resist the drill bit. It's akin to the difference between stainless steel and armor plate.
    - jessaustin 5y ago
      Oh I see; this may be similar to something we see sometimes with some very old concrete. Still, it isn't clear why this would be used in a residential setting.
      - bayindirh 5y ago
        Consider a gated community built very close to sea, where the houses are exposed to salty moisture all year long. Moreover the area is rocky, and is a very active earthquake area, so that a double wall sub basement/foundation is required. On top of that, the gated community is built by a company which is building dams regularly, so they're knowledgeable in specialty concrete mixes for both quake and moisture resistance. [This is not a hypothetical scenario btw. :) ]
- LeifCarrotson 5y ago
  Cordless impact drivers are one thing. Those store energy in a spring, a rotating hammer assembly is pushed by that spring and gains inertia, striking an anvil to provide a quick burst of torque. They typically have a hexagonal socket and are used to drive screws. Impact wrenches have the same construction, but are beefier, have square drive anvils, and are used to drive nuts and bolts. A hammer drill spins in a continuous motion, and is typically used with a spiral flute drill in a Jacobs chuck (or tool-less version of the Jacobs chuck). You can usually enable or disable the hammer action with the clutch. It has a similar mechanism that encourages the drill to tap forwards, but if you press too hard it won't do much. Just a weighty and useless add-on to an ordinary drill to justify a slightly increased price, IMO. A regular drill, even with a masonry bit, is ineffective in concrete; hammer drills can work if the bit is small and the mix used more sand and maybe fine gravel (eg. mortar or brick), but are hopeless if you encounter a larger stone. Importantly, the energy and the frequency of the hammering action are tied to the rotation - usually 1, 2, or 3 taps per revolution. You don't get heavy or rapid impacts at low RPM. A rotary impact (whether pneumatic, corded, or cordless) has an SDS head and a mechanism that drives the head forward and aft. You can typically run it in hammer-only mode, which is impossible with a hammer drill. You may be able to shift a cam (or adjust an air valve) to change the impact power. And yeah, with a decently powerful rotary impact tool, you can run put large holes in concrete with little hassle.
  - bayindirh 5y ago
    > hammer drills can work if the bit is small and the mix used more sand and maybe fine gravel (eg. mortar or brick), but are hopeless if you encounter a larger stone. Importantly, the energy and the frequency of the hammering action are tied to the rotation - usually 1, 2, or 3 taps per revolution. You don't get heavy or rapid impacts at low RPM. Hrmm, no. The drill I use (the 800W one) can drill up to 20mm on concrete. It taps probably 20-30 times per revolution and is able to drill earthquake resistant concrete with ease. It also taps harder if you push harder. This kind of concrete can resist thick steel nails when driven with an hammer. The nails generally break into two or get slightly bent. When used with a good drill bit, it just drills very cleanly with a little bit of resistance in the beginning, but makes relatively quick work of it. For reference, it's a Bosch CSB 800-2 RE, made in the 90s [0]. So, there are hammer drills, and there are hammer drills. Not all of them are created equal. [0]: https://obrazki.elektroda.pl/9414321300_1470304831.jpg https://obrazki.elektroda.pl/9414321300_1470304831.jpg
- fy20 5y ago
  I was referring to inserting fasteners, after drilling the hole with a different tool.

by fy20 5y ago

Haha. I have a cordless brushless impact driver. First time I used it to put a screw in a wall it went in so fast I didn't stop in time and it stripped the head :D

sam_lowry_ 5y ago

Cordless impact drivers or even 230V ones like Bosch Advanced Impact do not perform well on reinforced concrete. You need a pneumatic hammer drill. Visually they are quite different because of the SDS head.

jessaustin 5y ago
Lots of perfectly functional SDS hammer drills are electric (here in USA they're 120V). This is different from what I've called an impact driver, which is more for turning fasteners than drilling holes. Even Harbor Freight sells a few electric hammer drills that will sink smaller diameters like 1/4" at about 2 seconds per inch. Larger diameter bits take longer, but there's no need for an air compressor. I'm not sure why you'd mention "reinforced" concrete. I thought all concrete required reinforcement of some sort? Fiber won't be an issue, but if you hit rebar it's time to relocate your hole, no matter what you're drilling with. Even if the drill can do it you're going to ruin the bit.
- bayindirh 5y ago
  > I'm not sure why you'd mention "reinforced" concrete. I thought all concrete required reinforcement of some sort? Concrete can be tuned for brittleness and strength. Some versions become very hard and impenetrable after they completely cure. They need more powerful drills and longer drill times since they simply resist the drill bit. It's akin to the difference between stainless steel and armor plate.
  - jessaustin 5y ago
    Oh I see; this may be similar to something we see sometimes with some very old concrete. Still, it isn't clear why this would be used in a residential setting.
    - bayindirh 5y ago
      Consider a gated community built very close to sea, where the houses are exposed to salty moisture all year long. Moreover the area is rocky, and is a very active earthquake area, so that a double wall sub basement/foundation is required. On top of that, the gated community is built by a company which is building dams regularly, so they're knowledgeable in specialty concrete mixes for both quake and moisture resistance. [This is not a hypothetical scenario btw. :) ]
LeifCarrotson 5y ago
Cordless impact drivers are one thing. Those store energy in a spring, a rotating hammer assembly is pushed by that spring and gains inertia, striking an anvil to provide a quick burst of torque. They typically have a hexagonal socket and are used to drive screws. Impact wrenches have the same construction, but are beefier, have square drive anvils, and are used to drive nuts and bolts. A hammer drill spins in a continuous motion, and is typically used with a spiral flute drill in a Jacobs chuck (or tool-less version of the Jacobs chuck). You can usually enable or disable the hammer action with the clutch. It has a similar mechanism that encourages the drill to tap forwards, but if you press too hard it won't do much. Just a weighty and useless add-on to an ordinary drill to justify a slightly increased price, IMO. A regular drill, even with a masonry bit, is ineffective in concrete; hammer drills can work if the bit is small and the mix used more sand and maybe fine gravel (eg. mortar or brick), but are hopeless if you encounter a larger stone. Importantly, the energy and the frequency of the hammering action are tied to the rotation - usually 1, 2, or 3 taps per revolution. You don't get heavy or rapid impacts at low RPM. A rotary impact (whether pneumatic, corded, or cordless) has an SDS head and a mechanism that drives the head forward and aft. You can typically run it in hammer-only mode, which is impossible with a hammer drill. You may be able to shift a cam (or adjust an air valve) to change the impact power. And yeah, with a decently powerful rotary impact tool, you can run put large holes in concrete with little hassle.
- bayindirh 5y ago
  > hammer drills can work if the bit is small and the mix used more sand and maybe fine gravel (eg. mortar or brick), but are hopeless if you encounter a larger stone. Importantly, the energy and the frequency of the hammering action are tied to the rotation - usually 1, 2, or 3 taps per revolution. You don't get heavy or rapid impacts at low RPM. Hrmm, no. The drill I use (the 800W one) can drill up to 20mm on concrete. It taps probably 20-30 times per revolution and is able to drill earthquake resistant concrete with ease. It also taps harder if you push harder. This kind of concrete can resist thick steel nails when driven with an hammer. The nails generally break into two or get slightly bent. When used with a good drill bit, it just drills very cleanly with a little bit of resistance in the beginning, but makes relatively quick work of it. For reference, it's a Bosch CSB 800-2 RE, made in the 90s [0]. So, there are hammer drills, and there are hammer drills. Not all of them are created equal. [0]: https://obrazki.elektroda.pl/9414321300_1470304831.jpg https://obrazki.elektroda.pl/9414321300_1470304831.jpg
fy20 5y ago
I was referring to inserting fasteners, after drilling the hole with a different tool.