KEO 53514 Cobalt Steel Single-End Countersink, Uncoated (Bright) Finish, 82 Degree Point Angle, Round Shank, 3/8" Shank Diameter, 3/4" Body Diameter

Cuts A36 steel like butter, beautiful results!

I bought these primarily for when I build jigs for woodworking. I often need the holding screws to be flush, or even a bit sunk below the surface for my jigs to work correctly. I build jigs for my router, bandsaw, drill press, miter saw, etc.I have used the multi blade countersinks in the past, but was not satisfied with the finish that it left, often lobed, especially on plywood. The design of this countersink leaves a very nice finish.Now, I only use these for wood, so I have no idea how well it would work on steel. For wood, they work exceptionally well. In fact, they work so well that I have a small set of different diameters on hand.These are not the cheapest countersinks. I did like that they were made from cobalt steel. I also like that it is separate from the drill bit, it gives me more flexibility with how I use them.

These Keo countersink/de-burring bits are just awesome. They leave a much more refined finish than the fluted types I have used in the past. No chatter was evident when using on aluminum and steel. I am not sure how these would perform in wood applications, but will be attempting to do so in the near future. They're quite pricey for the application, but I have found no other that performs as well.There has been mentioning of these bits becoming dull, but I have not had that issue with its uses. I make sure to lubricate the metal and bit well and do not keep constant pressure on the bit, allowing it time to cool.

Standard KEO quality and if you don’t know what that means, if your a real mechanist and you care about finish quality. This is is. Those others suck and Irwin style leave your part chattery and nasty. You make race cars or parts that need a nice finish and have great tool life. Cuts both iron and aluminum.

I needed to countersink some hard maple. This is the first countersink bit of this type that I have used. It cuts perfectly round countersinks. I'm impressed.

Good quality, deburs drilled holes in metal.

It does not work on steel at least for me.

I only got one countersink with this bit. I am countersinking a 3/8" hole in a 3/8" carbon steel plate. It dulled after the first countersink. I am going to try a HSS 6 flute countersink next.