Ratings & Reviews for Kobalt Diamond Core Drill Bit 5/16-in Dry Diamond Core Drill Bit for Stone
Ratings may include incentivized customer reviews.
What Customers Are Saying
Customers praise the bit for delivering clean, chip-free cuts through porcelain, ceramic, and glass tile, with many reporting 8+ holes without noticeable wear. Success depends on proper technique: starting at 45 degrees, using water for cooling, maintaining low RPMs, and clearing debris. While most users who followed these methods achieved excellent results, some encountered durability issues like bending or grinding down, and a few struggled with initial hole starting on smooth surfaces. Overall, reviewers recommend it for those willing to use correct drilling practices.
Customer review summary generated by AI, including incentivized reviews.What I needed for the job
Worked out great
Verified Purchaser
Try to evacuate material every quarter inch….
Would RecommendWorked well. Takes a little practice starting the drill bit to accurately hit your mark since it doesn’t have a pointed tip. Since it’s more like s hole saw, it can sometimes be a pain trying to evacuate the material that gets lodged inside.
From Diamond Core Drill Bit 1_SLASH_4-in Dry Diamond Core Drill Bit for Stone Verified Purchaser
Porcelain
Would RecommendEasy to bit to use on tile. Cut through my porcelain tile well without cracking tile. It did take some time and steady pressure.
Verified Purchaser
Cut Clean Through Glass
Would RecommendI bought this to cut a hole in my glass table so I could mount it to a frame I had built. It worked very nicely and made a clean, smooth cut without cracking the glass. Took my time and it did exactly what I needed. I would definitely buy this again if needed.
Works great on granite!
Would RecommendFrom Diamond Core Drill Bit 1_SLASH_4-in Dry Diamond Core Drill Bit for Stone Verified Purchaser
Cut great
Would RecommendIt cut through my granit counter top easily.
From Diamond Core Drill Bit 1-in Dry Diamond Core Drill Bit for Stone Verified Purchaser
Thank you for the wonderful 5-star review! We're so glad to know our products are meeting your expectations. Your feedback encourages us to keep ... Read More
One more bit for the box.
Would RecommendChewed right through the TileMaster brand porcelain that Lowes carries. Several holes and it is still holding up fine. Keep the RPMs low. I keep a cup of water on hand to wet the cut. Again, keep the RPMs low. Helps to keep the cut nice and cool. If cutting thin material it actually helps to have a wimpy drill on hand. As other have stated, there is no pilot for this bit. But there is an easy fix. Jigs are the carpenter's best friend. Find a piece of thin wood, 1x4 or similar. Type is not re...
Thank you for the great 5-star review and for sharing your experience. We’re glad to hear the bit performed well on porcelain and held up across mult... Read More
Not an aggressive bit
Would Not RecommendDoes not cut well compared to other brands at this size
From Diamond Core Drill Bit 1_SLASH_4-in Dry Diamond Core Drill Bit for Stone Verified Purchaser
Thank you for your feedback. We’re sorry to hear the bit didn’t perform as aggressively as you expected. Our 1/4-in Wet/Dry Diamond Core Bit is desig... Read More
Thanks for the 5-star rating! We appreciate your feedback!