The point on this is 82 degrees with five flutes.
Yes, but keep the rpm's low as it heats up the steel and bit quickly.
I have used this on HardieBacker and re-pointed, then continued to use. Nothing holds up to concrete for any period of time without severe wear and dulling. If you want to counter sink, use Backer-on screws with a good impact driver. We now have a good impact driver and it is a breeze to flush out the Backer-on screws into the HardieBacker.
I would use it for deburring but, I would not use it for countersinking.
Thank you for your question. We would recommend a deburring tool to debur copper tubes. The countersinks are used for drilling into material, it would not be able to debur the sides of the copper pipe.
Thank you for your inquiry. The CST1 Counter Sink bit is used for deburring and chamfering openings to pre-drilled holes. For further assistance, contact us at 1-877-BOSCH99 (1-877-267-2499) from M-F 7a-7p CST.