VEVOR Diamantkernboor, 4 '/101 mm diameter kernboor, 9,5 '/241 mm betonkernboor, 5/8 '-11 draadkernbit, droog/natte boorkernbits, met een mes, diamant nat kernen bit voor beton baksteen

Was a little difficult to get started without the center bit. Once it started I was able to finish the job.

Ha funzionato per 2 volte poi i denti si sono rotti

I used the 4" dia version to cut a hole into my driveway to run drainage with an angle grinder. This core drill worked great, I used a piece of plywood with a 4"hole to guide my start cut. I can see how using this core drill horizontally would be much trickier, it's a heavy bit. I didn't break any teeth, and the bit held up well. I was in a low spot so it was easy to keep water on the bit. I was impressed with the results.A few observations. I bought the version without a pilot bit. This core drill is so long that the narrow dia. pilot bit would probably be a joke. If I had to use this bit dry I would take lots of breaks and put it in front of a fan in between.

Although I only have an old hammer drill (Hammer off) I drilled it wet. I first hammer-drilled a small hole through the wall. I then ran an evaporative cooler water supply line through the basement window into the inside of the basement. I inserted the water line into the small hole on the inside of the basement and stuffed some foam-rubber insulation around it so that water would come out to the outside of the wall in the center of the coring bit. I then mounted a piece of particle board with a 4-in hole in it to guide the bit. It worked really well! I am 70 years old and I was drilling the hole in a very awkward position but I'm quite happy with the way it turned out. I know that the bit teeth were wearing down, as they are supposed to, because I occasionally saw a sparkle of diamond dust in the water that came out. That coring bit is tough and it has several holes left in it!

I tried this core drill bit (no pilot) in three different drills, just to drill into Aerated Autoclave Concrete block (AAC). AAC is sort of like concrete styrofoam, it's fairly light and cuts easily with even just a handsaw.Myself and two others on my crew could not get this drill bit to work. It was very frustrating, to say the least.We tried coming in at an angle, and using it straight. We tried multiple drills, hammer drills, high torque, low torque, high speed low speed, corded and cordless. No idea why this didn't work other than the drill bit. I've seen people in videos online use this sort of core bit on AAC block, so I can only assume at this point that the problem is with the product.If the seller can tell me why this isn't working ans how to fix it, I will, and I will update my review.