12 Pcs Diamond Drill Bits for Ceramic, Diamond Hole Saw Drill Bit Set Kit, Premium Glass Drill Bit for Bottles, Pots, Marble, Granite Stone, Tile Cutting 0.16 Inch - 1.18 Inch（4 mm - 30 mm） YLYL

I got the 12 piece set thinking I’d go through a few of them just to get what I wanted done. To my surprise, I drilled through 7 planters and the one drill bit I used seems like it could endure some more work! It takes a bit getting used to (you can see the learning curve in the picture) but once you get the hang of it it’s easy. I started drilling gently at a 45 degree angle to first create the initial dent that will allow the drill bit to stop sliding - tape also helps provide a good initial grip. I then added water as I drilled. Remember to wear eye protection in case small sharp pieces fly out (I just used my big thick sunglasses). Lastly, it does get a bit messy, I did the work outdoors while wearing clothes I don’t care for. Happy to now have proper drainage in planters I love

Worked great. Like butter. Use a fresh drill battery and spin nice and fast.

Well now that I've used them they are good enough for the price. I've had a set for a month, and I've tore three of my main use ones up 18, 20, 22. Main problem is they don't cool good and they can't handle real torque. So if I'm drilling Jasper or agate it's slow and careful.The ones that broke18 mm eventually wore out20 mm melted22 mm the weld twisted offMind you I am using a 1968 sterling 12 speed drill press with a counter weight set drilling and water cooled. So it is definitely probably too big for these bits.Going to go oil cooled and see what it does, I know my saws like oil.

I have lost a few pots and plants due to holding too much water for lack of drainage holes. I was a little nervous to drill, but they worked! At first I tried to drill straight down, but my husband tipped me off to angle the bit and do one edge first to bite in, then bring upright. Worked great!I did get a couple chips on the edges, but it's the bottom of the pot, and no cracks, so no big deal. Probably user error than the bit. I did 6 holes with one bit, could probably drill a few more, so I'd say that they are fairly durable. The pack is a good value for number of bits.

Understand that these are all in metric sizes and this purchase was for the smaller sized bits. There are many sizes to choose from in this kit, from I think 3mm or 1/8 inch equivalent up to I think 24mm or like 7/8 inch. The sizes are laser etched on the shafts and are a little difficult to see, but the holes that they make are relatively smooth rather than just a sharp edge. The reason is that the bits are simply metal tubes that have one end dipped with metal covered crushed industrial diamond, much like sprinkles on an ice cream cone. With this said they are not lab quality sized bits, and have some cutting surface disparity due to the various sizes of chunks around the end, and this disparity will create a more rounded or smoother edge on the hole that you cut through the glass. Start out slow and at an angle with just the weight of the bit against the glass, and spin the bit against the glass until a little edge develops (I used a rechargeable drill), then add a few drops of water and start to reduce the angle and the edge starts forming a circle on the glass. Slow and steady wins the race!! This is glass, and super tiny pieces of glass are now being broken off of what ever you are drilling through so wear a mask, and have a removable work space that you can just wipe and clump up into a ball and throw away, like some damp newspaper that the wet paper will keep the super tiny glass fragments/shards from blowing away and you can just crumple up and throw away the mess with minimum wiping. With this set I managed to drill a 1/2 inch hole in the side of an aquarium for a water overflow, on one of those 2 1/2 gallon rectangle super thin glass aquariums with the black plastic frame, that still had some fish in it (do not recommend this). The hole was a success, the fitting has been installed and still the aquarium has fish in it (that suspect nothing.) Slow and Steady, listen to the screeching of the bit against the glass, if too much screeching you are either too fast or pushing too much. Slow down, add a few drops of water, and then continue on until you start to see the point where the water starts running down the glass on the other side, then slowly continue on until you have a hole drilled through whatever it was you were drilling. Note: I do not know what it would do to tempered glass, from what I know this would probably shatter any tempered glass the instant the bit scratched the surface. My use with these bits has been just plate glass and bottles. Good luck.

Didn’t work well for me. I was trying to drill porcelain and it could barely get through.

Works very well, also the different assortment of sizes is very convenient

Used these on my ceramic planters and the worked out great. There was a variety of sizes which is very handy. made out of good quality material for what I needed it for.