BOSCH CSH1 1/2-Inch HSS Countersink

I use them for all materials, everything. I keep one in the case of each Milwaukee Fuel drill. I debur almost every hole we drill with them.

I have a 60 year old bathroom exhaust fan. It began to squeak and squeal. Rather than replace the motor, I drilled a small hole in the bottom of the housing at the bottom bearing and smushed axle grease in. Sounds quiet and runs great again. Saved about $100

I used this to countersink screw holes in a mild steel sheet. It did the job, though it chattered a fair amount. I used WD-40 to lubricate, and tried drilling at a variety of speeds, but I struggled to make a smooth countersink. In the end this doesn’t really matter, since the countersink is hidden by the screw head, but I had hoped for a smoother result. The bit did the job, and doesn’t seem to have dulled.

This worked quite well for my application which was the creation of a countersink in some mild steel plate. The plate was around 1/8-inch thick. To extend the life of the bit I made sure my workpiece was solidly clamped onto my drill press and I used cutting fluid. This was probably a near-optimum usage environment...so your mileage may vary. I picked Bosch because of previous experience with tools from this manufacturer.

The design and material of this countersink is great; the five flute design minimized chattering, and it's made of good, hard steel, suitable for use in metal as well as wood. The design is especially important when using it with a hand drill, as it will cut a smooth hole even by hand (though obviously results are better with a drill press).The quality is only decent; as other reviewers have noted, it came with some small burs and nicks in the cutting edges. Not enough to make much difference cutting in wood, but it does impact cutting in metal. However, I was able to clean up the edges fairly easily with a fine grit sharpening stone, and after that it cut great in mild steel. I've also sharpened it more than once over the couple years I've had it, after lots of metal drilling dulled it. I had to be careful to sharpen each flute the same amount to avoid unbalancing the cutting action, but all that takes is keeping track of where I have and haven't sharpened. The bit has cut well and smoothly after resharpening.

Sharp and cuts clean. I used it to countersink holes in 1/2 inch aluminum. Holes were clean and round. Will buy again.

Great little bit, does the job, makes countersinks, seems sturdy.

BOSCH does usually make very fine products. Quality betters price almost every time.The picture is not correct. It actually is gold colored.This bit in particular has shown no signs of wear after several uses which is good to see. Much harder than previous bits I had that wore out and I replaced with this one. It also is fairly sharp so do not press too hard in wood.If this wears out, I will make sure and buy another one of these.GOOD product, well worth the money