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

The tip of my bolt extractor snapped off when using it on one of the bolts on the underside of my lawn mower deck (the bolt head broke off), the bolt was old and rusted. Two days of penetration oil didn't do enough. So, the bolt extractor was used to get the bolt out...that was a no-go when the tip snapped off and was fully stuck in the pilot hole. These bits were purchased to see if they'd help in wearing down enough material to get the bolt extractor tip out before I drilled through the bolt and re-tapped it. The extractor being a far harder steel made using my usual drill bits a no-go in attempting without something like diamond coated hole saw bits. So, with as many as come in this pack, I figured why not? It's cheap and a useful test. I went through about 4 of these, ensuring I kept the bits cooled with a container of water (dipping the bit in ever ~5 seconds of drilling), over the course of about an hour. Gotta go slow, don't apply more than a very light pressure if any, let the hole saw do its thing by abrasing the metal slowly. Worked great, the extractor tip fell right out eventually, and I've got a bunch more of these for the next time!

Work good

Very good drill bits, they serve their purpose. I used them to drill river rocks and although the process is slow, it was possible.

Can I give this a ten star review? I have tried every bit available for drilling holes in glass. I’ve used full sized drills and I have sued my dremel flexi shaft. THESE BITS ARE THE ONES! Most bits wear out quickly after a few pieces and take forever to get the job done. One bit drilled all of these pieces in less than five minutes. And there’s more use on the bit too. Long lasting and perfect. Worth every darn penny!

These worked well on porcelain tile in the shower. They cut like a dream.

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.

Five star! I've only used one drill bit but so far this FAR outperforms the dremel glass drill bit. I have so far drilled more than 15 holes with the first drill bit of the package. 15 holes and it still has some life! I have drilled through rock, glass, and shell. In comparison the dremel glass drill bit was only used on glass and I maybe drilled 12 holes before it was useless. The size of the hole this bit makes is a little larger than I expected but I take it into consideration for what I'm drilling. The one complaint I read about and is a bit of a problem is the length of the hollow core of the bit. After each use I have to use a metal pick to punch out the stone or glass piece that is in the bit by sticking a metal pick through the small side hole. And if whatever you're drilling through is thicker than the hollow core of the bit you have to stop short and break off the nub inside the hole before proceeding. This bit is so much better and cheaper than the dremel bit that I will happily adjust for the two issues I mentioned above.

Ordered these bits to drill holes in my fused glass ornaments. I used a drill press for the work. So far, I’ve drilled over 50 holes with one bit and it’s still good to go! Love these 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.

I was easily able to drill a hole in the bottom of a glass vase. Obviously I made sure that there was lots of water for cooling. Would recommend.

JINGLING 3 mm 1/8" inch Diamond Hole Saw Core Drill Bit 's outdo what they advertised. I used the diamond bits through quartz crystals & they worked really well I'm impressed !

These were exactly what I ordered shipping time was great .Useing to drill sea glass and they last well drill good and have cut breakage