I was after a decent set of countersinks for some wood projects, actually, but i do some steel-work and welding, too. So i figured...why not get a set that covers both? That was my reasoning, and these seem to be a very decently cut set. It's hard to beat cobalt for an affordable choice in long-term duty and efficiency. There's carbide, too, but that is a very expensive choice and way out of my financial league. In use, these work very well. After all, a countersink doesn't normally face much stress in a wood environment. But out of interest, i did try a couple of these out on some steel. Again, they worked fine although of course much slower. I wouldn't want to use these too regularly on stainless steels but they do work, if you need that. They just won't work as long. Of course, on aluminum they would work really well. Just remember that a little oil helps keep the tip much cleaner and clears the chips efficiently on aluminum. These are great bits. Remember, though, that these will only work in a drill chuck and not in an adapter or nut driver bit because these are not hex drive. There are others available if you need that, but most people would use these in a chuck, anyway, i think. All in all a nice cobalt countersink set. Don't confuse these with a cheaper HSS set.

I’ve been searching for taps like this to help with some wood projects. I don’t always have the same kind of screws so being able to counter screw eliminates any issues with the heads interfering with the build. Good value for money. Sharp and good fit and quality.

The 2 that I have used so far performed better than expected. I used at low speed and with cutting fluid to prolong there life and get good finish results. So far, they seem to be a good value.

If you think that a “countersink” is something to wash dishes in, this product is not for you. On the other hand, if you’re a craftsman, machinist, builder, maker, or tinkerer, you know that a countersink can be used for a variety of tasks including deburring and “breaking” edges on holes, as well as creating the necessary relief to allow a flat-head screw to lie flush with the surface it’s driven into. Here’s a nice set from ColumPRO. The kit consists of quantity-five 82-degree countersinks in 1/4-inch, 3/8-inch, 1/2-inch, 5/8-inch, and 3/4-inch sizes. The bits are said to be fashioned from “M35” cobalt steel, for toughness. The kit is contained in an unusually robust blow-molded case. The flutes on these bits are reasonably sharp, and bite happily into plastics and aluminum, the materials I work most frequently with. I have no doubt they would perform similarly well in mild steel. I think this product represents a pretty decent offering at a $25-buck price-point. We’ll have to see how those edges hold up over time.

I am a DIY homeowner and I am in the middle of building a 30x10 deck. I noticed that my current countersink bit was chewing up the boards. I ordered and received the set of Cobalt countersink bits. I was (and still am) amazed at the difference a sharp bit makes. I have drilled hundreds of countersinks since receiving these new bits and they still perform like they are brand new. I am even removing some of the early deck screws that I installed, lightly grazing the countersink, then reinserting the deck screw.

These are obviously not top of the line, but they work great. I had to enlarge the hole on a hitch pin and then chamfer the hole, and these did great. Granted, I assume the metal used in the hitch pin is not hardened tool steel, but I assume it's harder/better alloy than common mild steel. These did an excellent job. Once you get the pressure and speed down, they cut really well. I would have no reservations about using them on mild steel, and would likely give them a go on harder steel or different alloys. Overall great. These might not be the best match for an everyday machine shop, but for ordinary and occasional use, they are great.

I chucked the 1/2" and 3/8" bits into my drill press and they cut smoothly into 1/4" aluminum bar with no problems leaving a countersink depression ready for the center hole. Similar result using a scrap of 5/4 maple. I would normally prefer 3/8 or 1/2 shanks for the drill press chuck. Using a hand-held cordless drill, I found the bits wandered a tiny amount on startup in the hardwood and slightly more on the aluminum bar stock, but that's to be expected. The plastic case is a nice touch but opening and latching closed 3 times rendered one of the 4 latches unable to latch. The case overall seems thin and flimsy, but I'm here for the bits.

"These work well. When used in my drill press they never leave a chewed up or burnt hole like my previous cheap set did. I pretty much only use the 2 largest sizes, I'm not sure if I ever use the smaller ones from any set I had. Having a case is good but this one with 4 latches and a string wouldn't be my first choice, it has a soap-on-a-rope vibe. These have taken the spot of my everyday countersincs"

This review is for the olumPRO 5PCS Cobalt 5-Flute Countersink Drill Bit Set. I have had three countersinks for years and have used them on many projects. Problem was they were not always the right size for the flat head fastener. Along comes this set at a reasonable price point and 5 sizes that work all the way down to a #2 fastener. They run true and cut well and it's a big plus that they come in a little case so they don't end up getting scattered around the bench. Tried them out with wood, plastic and aluminum and they did a nice job.

I'm pleasantly surprised with the quality and function of this set. I was reluctant, given the price, because I normally pay about the same for a single bit from industrial supply houses. They are sharp, and cut clean on wood and brass. No chatter at all on those soft materials. There was minor burning on white oak, but the cut was clean. They cut like butter on plastic and mdf. I chamfered some holes in steel hinges just as easily. Just remember to adjust the speed for various materials and these will serve their purpose well.