If I ever do this again, I may just mount an air powered cut off tool with an abrasive disc to the cutter instead. As the disc wears, the whole assembly can be lowered by turning the nuts that are sandwiching the cutter. It was a LOT of work for SWMBO to hold the keg still and a LOT of work to turn that cutter. I have a newfound respect for 304 stainless steel now... lol. I was sweating like crazy by the end. The screeching noise was unbearable. The cutting oil I used was actually smoking from the heat. It was not as elegant of an operation as the pics might suggest, but I did end up with a perfectly round hole in the keg!