Ah sorry I was unclear about what I was saying, I went off on a tangent unrelated to the sprocket thing. I meant when you file the cutting teeth back, at some point they supposedly get no wider than the bar and the bar binds in the cut. This has never happened to me as I've yet to wear out any lo pro chains at all from filing the teeth way back, but I was told my someone who runs standard bars that this occasionally happens to him on chains he's nearly worn out the teeth on. Another thread I posted on today I started checking all my bar widths with calipers, and found my 36" GB lo pro bar was the same width as my 42" Stihl .063 Rollomatic ES bar, and most all my regular 3/8 or. 404 bars, so there isn't actually a difference there. I think BobL did some tests years back on actual kerf produced in cuts, and 3/8LP was producing a kerf of .28-.29", where the bar width is .19", so I can't see you ever being able to file the cutting teeth back so much they're only at bar width.