Since my last post I've learned that augers with their screws removed are called barefoot augers. They are rare but not unheard of. Since Lars had complained of the screw on a new auger of his that we hope to use, I suggested that we could turn it into a barefoot auger. It turns out that he already had a better idea!
He is fabricating a pilot spade bit that will screw onto the auger's feed screw. I think this is a great idea and can't wait to see if it works. If it doesn't, then we can always resort to hacking off the screw.