I really like to be able to countersink screws so that you get a nice clean look on the finished wood. I hide screws as much as possible in my work but finishing the holes is just one more step to giving a high-quality hand-crafted feel. I'm using them in hardwoods from mor common Oak, Maple or Black Walnut to exotics like Cocobolo and they are cutting perfectly. The 4-cutter design helps minimize blowout and probably significantly reduces chatter in metal but I haven't used them on metal yet.

Product works to bore holes as needed. Comes with a handy case to store bits.

I’m finishing a cabinet and love the finished look of countersunk screws. These bits work great on wood and leave a smooth finished hole. I haven’t tried on steel yet, they seem sturdy but not sure they’re really cobalt? Guess I’ll try and see. I took off a star because there is no storage case, which I’d expect at this price point. Still, I do recommend these.

Works as it should. Great price. And very durable material. This is a daily user at my job.

I wanted to repair a stripped hole. The correct size worked perfectly for that, then I put in a dowel. Easy peasy. I don't have a lot of experience with this type of thing, but I'm not sure I would try and use these on metal. They seem sturdy, and did the job I had for them very well, but they don't cost enough to be made out of the material they say they are made out of. I recommend these for wood.

It’s a great set. I was a little surprised it didn’t come in a real storage case. Very sharp from the get go. Just make sure you have the RPM up so it doesn’t give you that “Star” shaped countersink.

I have countersink bits, but not cobalt. These are really nice, and work well for cleaning out holes drilled in sheet metal and that's what I use them for. Without a lot of pressure, they'll deburr the hole quite well, or enlarge the hole if you want them to and use more force. Naturally, they'll work on wood, but you don't need cobalt for that, and I have a slew of other bits that do the job just fine. They came in a cardboard case, but the bits were set in foam, and the top had some sort of a plastic overlay. So you can remove that from the cardboard box and set it in a toolbox or toolchest drawer and it will keep them nice and organized and even labeled. This is a good set of countersink bits, I'm happy with them.

If you do any woodwork and use screws to hold anything together, you really need to use a countersink bit to prevent the veneer from splitting. These are M35 cobalt and extremely sharp. Cobalt steel lasts a very long time. Since they are Cobalt steel you could use these on metal as well. If you use them on wood they'll practically stay sharp forever.

Received item in good condition - fast shipping Not the correct color for Cobalt seal - didn't actually expect Cobalt steal for this price, I will not be using these for countersinking in real steal, every China made countersink drill bit I've tried immediately dulled and become useless, I got these to clean the burs off seal drilled holes, they should fit my hex hand driver nicely, would have been nice if they just would have come with handles, Might recommend them for what I will be using them for, not for what there calming to be for

I have another set from the green brand. The green brand does have a drill bit incorporated into it. Most likely those are made just for wood. These seem to work better and cut in a cup shape. I only have used these in wood and worked fairly well. The insert in the box is nice but it would have been really nice to get a plastic case instead of cardboard.