Sscon 30Pcs 2.0mm Diamond Coated Hole Saw Drill Bits Carving Drilling Hole Tools for Jewelry Gems Glass

These are great, use for drilling glass and the are the best I have ever purchased. Usually only about 10% work due to lack of Diamond grit on the end. They tell you to start drilling at an angle as have to use Diamond grit on them edge. These have a very good converage on the ends and first one out of the pack drilled over 50 holes in 1/8” glass and is still going. They also drill 2-3 times faster than other 2mm bits. These are awesome.

Worked great for drilling rock slabs and cabochons, must absolutely use water to keep bits cool,1 bit lasts through a couple dozen slabs, quartz and jaspers.

I recently purchased JINGLING 0.4mm Diamond Hole Drill Bits to work on some formed epoxy dough (think of it as having a toughness somewhere between dried, unfired clay and actually fired clay) and in about 2 hours the tips of 5 drill bits broke off...and all I was doing was etching simple lines on the material's surface. Absolutely pathetic.However, I don't know if it's because this is a different manufacturer or because these are slightly bigger (by a whopping 0.1 mm), but I have yet to have a single SSCON bit break on me. They work a LOT better and, amazingly enough, were a lot cheaper, and provided 10 more drill bits than the other brand.

Slow AF to use, but they will grind extremely hard metal (hardened steel taps broken off in soft metals, such as brass, zinc or aluminum) accurately, without wandering from where you put it. Use 'em in a drill press or a mill, might be good in something like a high speed rotary tool as well. After a half hour of grinding, the diamonds appear to still be intact, and they still cut (slowly). Still, these are lifesavers if a tap breaks off in a hole, and the slow speed of cut is made up by the lack of wandering in the hole. Cheap at the price.

I ordered these for drilling holes for findings in quartz. They fit well in to my multi tool and haven't cracked the quartz. I don't have much else to compare these to.

These work very well for drilling small pebbles. The only reason I took away a star is that they are very short so if the pebble has any thickness at all, it widens the hole at the top.

They are the perfect size for drilling holes in stones for the eyescrew but they break very easy

Just drilled a few agates and the bits work great. Diamond surface cuts aggressively and held up well.