"Dave Liquorice" wrote in message
ll.net...


I've yet to see a PZ bit that didn't have the corner sections in. I was
under the impression that they were part of the design rather and a
manufacturing restriction.

They are caused by having to have the grinding wheel at 90 degrees to the
shaft.
Its damn difficult to not have them using grinding wheels to shape the
blade.
I believe I saw some that appeared to be forged to shape and they didn't
have the leftovers.