JINGLING 3mm Diamond Drill Bit, 1/8" Diamond Drill Bits, Glass Drill Bit, Coated Hole Saw Core Bit Tools for Stone Tile Pack of 20Pcs

they work well when cutting Sea glass or Agates

I am trying to drill holes in polished rocks to mount them on rods and while these drills do cut a hole fairly well, given their design they can't cut more than about 1/4 inch before the hollow shaft fills up with rock and can no longer drill. I need holes at least twice this depth.

I have only drilled 6 holes so far, but I am still using the first bit. I have drilled marble, slate and granite all with the same success. If you are drilling a deeper hole, snap off the column created by the core bit so it does not bottom out in the bit. Also, use a small wire to keep the bore clean. Sometimes you have to crush the material in the core of the bit to get it out, but just insert a small screw driver or nail - i uses a masonry nail sharpened to a point - and the bit keeps on going. Don't press hard on the tool and you will see the water get cloudy around the bit as it cuts through the material.

Looks like a quality product that will do the job for a long time.

Got the drill bit and start using it to drill my porcelain tile floor. It is definitely the right tool as normal drill bit hardly makes a dent on my floor. As I start using it, I found 2 issues:1. The drill bit wears out on each of the hole that I drilled. Basically, half of the tip was gone and it's no longer sharp enough for the next hole.2. I melted 2 brill bits when I didn't stop in the middle of drilling. If you put on high speed, the drill bit will melt in less than 2 min. If you put on low speed and didn't stop after 3 min, the drill bit will start to bent as it gets soft.I'm not complaining as these drill bits are fairly low priced and I don't mind throwing away the bit after 1 successful drill. Just make sure you don't have the expectation of using it over and over if you are drilling hard material such as porcelain.

I've struggled with multiple types of diamond encrusted drill bits with no success, but I'm thrilled with these. I've been drilling holes in 6mm or more glass pendants all morning with no problem and much quicker than solid bits. To add to the pleasure of working with these bits, I've had no blow out on the back side. Just nice clean holes all the way through.There is an occasional noise when drilling that I think is the core moving up into the bit. Don't let that bother you.The only problem I have now is my lousy judge of the center of a thing but even that I can fix with these. I just gently push in the direction I should have gone and make a wider hole. Then I make a bail to keep piece from sliding within the wider hole.

I purchased a diamond bit drill from my local hardware store. It took more than 10 minutes to cut a piece of beach glass. I ordered these bits, they were less expensive than the one bitt from the hardware store. It took less than 20 seconds to cut a piece of glass. I tried a stone found on the beach. That did take about 4 minutes. One bit lasted for 15 pieces of glass and one stone. I am so impressed and happy with this purchase.

Worked great for drilling through my gemstone cabochons.

These have become my go-to bits for drilling pendants. They do a great job of cutting smoothly and cleanly through any Stones, even quartz.Being a hollow core drill bit, they do need to be cleaned often. I use a push pin to clean out the core. I find they are generally good for five to ten pendants.

really nice drill bits that will cut through anything up to quartz hardness, but due to its size it is difficult to keep the core free of debris, so the bit plugs up on the inside and becomes useless. The three mm version of this bit is much easier to keep clean

Good to start with this to do a small hole and finish with a bigger bit. Good to have many because they wear pretty fast even with watering when drilling. Did the job for me with multiple bits

Great for drilling through our beach rocks, sea glass and shells. Found these to work best so far. We use in our drill press and they last a long time. I ordered more.

Keep the bit wet and you'll be fine.Looks cheap, works great. I drilled 6 holes with 1 bit in ceramic floor tiles to see how far a bit would go