KEO 53512 Cobalt Steel Single-End Countersink, Uncoated (Bright) Finish, 82 Degree Point Angle, Round Shank, 5/16" Shank Diameter, 1/2" Body Diameter (2-(Pack))

I did not know it was possible to adore and cherish a countersink bit so dearly. It cuts buttery smooth with no chattering at all. Pictured is a comparison on birch plywood with this bit versus my old crappy fluted set. I'm a cross-hole countersink convert for life and am now working on evangelizing all my friends.

This is the BEST countersink I've EVER Used. It cuts cleanly and smoothly without chattering or tear-out, using both drill press and hand held drills, in every material I've tried it on: Woods incl. veneered plywood, soft pine, poplar, red oak, and walnut: Misc plastics: Metals incl. cast-iron, and mild steel. It's performance in hardend steel is unknown to me at present, but I'm still calling the KEO Countersink... AMAZING!

I bought 2 of these thinking they would probably get dull before I was done with the project I was working on countersinking 1/4" holes in pipe rail ties for #12 flat head screws. I set my drill press at 540 rpm and used cutting oil on every hole. I countersunk 264 holes in about 2 hours with the same bit and it still cut just as good on the last hole as it did the first. It was pretty much mild steel, not stainless, but I was still impressed. A great tool for the job I had.

I needed to countersink some holes in 316L SST. I only have a drill press, not a mill. The multi-fluted c'sinks were chattering like crazy. This did the job nicely. Not perfectly, but very nicely. Considering my simple setup and the hardness of the sst I am pleased. I would definately seek out others like this if I need more countersinks.Peter

I used this counter sink for the first time today. It's half the cost of the CRlaurence brand and works just as good if not better. I used it to counter sink 3/16 aluminum extrusion. After 500+ holes, still sharp. Definitely recommend for others and will definitely buy more to have in my stock.

Unbelievable to put a countersink in 3/8" aluminum with an old cordless drill. Just peeled off like a potato skin. Go slow with even pressure. Looks professional. I had to drill the 2 closest holes to you out for the next size bolt. Took about 15 seconds per hole.

This cobalt bit held up to several hundred countersink holes in 304 stainless using a drill press with cutting oil. This bit has had a much longer life than previous bits that I used which were HSS. Because of its low cost and long life I will definitely buy the same one again.

this makes very nice smooth countersunk holes without chattering like multifluted countersinks often do.I wish it had a longer shank as when you use it on a drill press to c-sink a hole its often too short compared to the bit and you have to raise the table which loses the centering you'd like to have to make sure the hole is concentric.