SHDIATOOL Diamond Core Drill Bits 1-3/8 Inch for Hard Stone Concrete Marble Granite Brick Laser Welded Dry or Wet Hole Saws 35mm

I was amazed at how fast these drill bits can cut through brick. I used them on a battery powered side grinder and cut through 3 inches of brick in just a few minutes. They made ideal holes for both electrical and plumbing conduit and the results look much better than breaking out the brick with a chisel.

Wasn't sure how well this was going to work but was pleasantly surprised with results. I bought two of these SHDiamtool core drills, a 50mm and a 32mm for custom work on sandstone blocks 2 to 2-1/4" thick. I had 12 blocks that needed one 2" hole drilled completely thru and four 1-1/4" holes drilled an inch deep, not all the way thru.These drills do not come with a pilot drill, so I made a template out of plywood and 2x4s with the same hole sizes and layout as I needed for the blocks. That made it easy to be sure the drill didn't skip or wander when making initial contact with surface of stone. I used a drill press with water coolant and checked a core drill speed chart to make sure I was in the ball park for spindle speed - used 1080 rpm for both sizes - and these things cut thru sandstone really well and quite quickly using only moderate downfeed pressure.This pair of core drills performed well and did exactly what I needed - I would buy them again, but they hardly show any wear on them after 12 holes with the 50mm and 48 half depth holes on the 32mm. Make sure you have or buy the correct arbor for them and you should have no problems if you keep them cool with water, use the correct spindle speed and don't use too much down force.

I can't speak to it's longevity or durability as I only needed it for this one job, but it's a well built tool. It went through the tile and concrete in a couple minutes. Wasn't great at going through the wood. It pretty much burned it's way through sub floor. For this 4in diameter I recommend using a plug-in grinder for the power.Overall happy with the performance and ease of use. Definitely use earplugs, a mask and safety goggles. It makes a lot of dust. Follow the instructions. The hole was exactly where I wanted it, did not walk off center at all.

I bought two bits. Can’t beat the price. The first burned out after boring three 5/8” holes when I had my variable speed grinder set at medium-high. I then drilled nine more holes at medium speed while cooling the bit every 8 seconds in water to not burn it out. It worked well although tedious.

I received it within one day as promised! Put it to use on my sidewalk and it worked fantastic! Similar at home Depot and Lowe's were $200, save me a lot of money, a lot of time and it worked fantastic! Highly recommend!

It worked really nice for probably the first 20 holes I drilled. Works great in engineered quartz, but struggles with natural stone especially quartzite.I was cutting the four corners of a sink in granite today in one of the teeth just came apart. Glad it didn't hit me. As you can see by the picture there's still a lot of meat left on the teeth so I should have got a lot more use out of this bit. I didn't necessarily mind the slow cutting in natural stone too much, but the safety factor of a tooth flying off at mach Jesus earns this a 1 star

Installed lights in my brick paver driveway, used this bit to drill the holes through 3 inches of solid brick. No problems at all, I set up a garden hose to trickle water going down drill bit through hole and this bit has lasted a long time. Money well spent

I was apprehensive about buying such a reasonably priced core drill. I needed holes bored in a new 4” thick concrete counter top, out on our patio, but didn’t want it chipped out. I bought this and kept looking at it, worried it wouldn’t work, or worse, I would wind up with ugly holes.. So, I’m here to say, this little core drill, drilled 8 holes through 4” hardened concrete with ease ! I even used my battery ryobi drill to do it. I drilled the holes dry, because it’s adjacent to my new fish pond and didn’t want a slurry on cement getting into the pond. This little bit drilled 8 dry holes using a battery powered drill, in under an hour, with smooth unchipped results !Impressive !Rich…