Aleric Countersink Drill Bit Set,High Speed Steel Counter Sinker Drill Bit 5Pcs 5 Flute 6mm Hex Shank with 82 Degree Mill Cutter Bit Countersink Bits for Wood Metal in Size 1/4” 3/8” 1/2” 5/8” 3/4”

Excelente

Good

Kept sharp after I used it to drill out a hole in my aluminum heat sink for a 3D printer. The cut was clean, more than good enough for my low tolerance application. Considering the price it seems like a great option.

worked very well in Trex building materials. remained sharp.

If you’re wood working with these they may last forever. I used them to make a custom router table regarding the flush top dropping screws into a rather simple setup. I milled through aluminum and after running a wire brush over the blades after each use they continued to plug without slowing down on my drill press. Only made 8 holes with a single bit, but I was impressed.

I thought these things might be the greatest things since sliced bread. I was underwhelmed. Ignore the hype and just look at these as decent concrete/cement bits. They did not work on glass, the tips wouldnt bite to get the hole started and it skated all over the place in a hand drill. Same on tile, tho if i started.the hole with a conventional tile bit, i could finish the holes with these. Strong 3 out of 5.Follow up after a couple more months....I have found that these are useless for starting their own holes in pretty much anything but rough surface stuff like brick and concrete-where they work well. They are fantastic reamers tho, once you have made a hole with another bit, even in soft steel. Where they excell is in making holes bigger in ceramic or porcelain tiles and concrete backer board. The other day I had to drill 42, 1/2 inch wide holes in tile to mount handicap assist grab bars (the toggles require 1/2 inch holes, six holes per bar). I made the initial holes with 1/4" diamond hollow core bits til i got thru the tile, then switched to these bits and very very very quickly reamed the holes out to a bit over 1/2 by tilting the drill at angles and it made an extremely smooth cone shaped depression with absolutely no cracking or chipping of the tile; unlike the ragged hole i made with a conventional straight tip concrete bit I tried first (nasty hole, out of round, chipped edges, very scared I might break the tile). Seriously, with a starter hole, I went up to 1/2 inch in seconds. No signs of dullness after more than 50 holes. Good buy, glad i did it. Oh i also appreciate the sturdy little carry case, keeps them organized by size and easy to find in my shoebox full of conventional masonry bits.

So you know the color is not as bright as picture displays, but this has nothing to do with the functionality. I have used 3 of the 5 many times and they perform well. I'm expecting them to last a long time from my moderate usage.They come in a small zip-lock bag inside a small tin container with a viewing window in the top of the tin. I removed them from to bag and placed them in the tin free-floating. Nice to have a container to keep them from scattering in my tool drawer.Hope this helps.

I was getting a lot of shatter with these until I increased the speed and used less pressure. I now get perfectly smooth counters ever time. I bought them for use on soft wood only. Don’t know how they would perform on hard wood or steel.