Bubba's explanation makes sense to me as well, though I've got to confess I wouldn't be surprised if the opposite were true - I simply don't know & don't claim to. I was surprised a bit by Skimo's post/reply about trolling. I'm sure I'm just not aware of some history here or something, but just reading it isolated in this thread made the reply seem a tad...aggressive. Even if Bubba is 100% wrong, he believes he's right...so why is being possibly misinformed "trolling"? And at the risk of sounding even less cool than I do already, isn't trolling done on a boat with a small motor while fishing?...sorry Skimo, I'm the Dad who tries to act cool in front of my kids' friends by saying "isn't that rad?". Anyhow, I would like to know which of you is really correct as I've often wondered about chisel grinds myself, but not enough to actually research it myself - thanks for the neat-o thread OP.