Irwin Industrial Tools 10239CB Unibit 2-Steps Cobalt Step Drill Bit for 1/2-Inch and 3/4-Inch KO

I purchased this Unibit to convert stainless beer kegs (purchased legally from a brewery, not stolen!) into a 15 gallon system for home brewing. I had 8 holes I needed to drill out to ~1" to accommodate a 1/2" stainless female coupler. I did my best to keep the RPMs and feed rate down as to not work harden the stainless but despite my best efforts, the bit really struggled from 3/4" on. Part of the problem was maintaining the proper speed and feed with a hand drill but part of the problem was the burr formation on the bit as I used it. This started to happen around hole 5 and was somewhat surprising considering the hardness and price of this bit. Once the burrs formed, hence dulling and generating heat, my speed was no longer the problem due to the bit's inability to cut. The bit really struggled to make the 1" hole even when new but cut very easily through the stainless for smaller holes. Perhaps a large drill press would do the trick but this was not practical for my use. If using this bit with stainless, watch your speed and feed and keep it cool as possible and stick to smaller holes. My bit will never cut another hole above 3/4" which is very disappointing considering the price I paid for it.

It might be the single cutting surface, but this was the slowest bit I have ever used. It created a lot of heat as well, the only positive was the spacing in the middle that made for a clean accurate hole.

Item just as described, fast shipping