SHDIATOOL Diamond Core Drill Bits 3 Inch for Hard Stone Concrete Marble Granite Brick Laser Welded Dry or Wet Hole Saws 75mm

I used this to core drill 6 holes on my granite tread steps, it works great with the corded hand grinder! I use the garden hose to spray water as I’m drilling. The core bit still looking great with no signs of damage! It exceeded my expectations! Excellent product!

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.

Drilled a smooth quick hole in brick but one of cutting teeth broke. Don’t know if will still cut effectively.

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

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

I purchased an 1.25" and a 1.375" one. also adapters for my cordless. They cut great and fairly easy to control that way rather than full on or full off like peanut grinders do. Variable speed is wonderful (says the guy who only does 4-5 holes a year).

Muy bien gracias