Hank, forgive me if I'm stating the obvious, but here's my 2 cents. (This may have nothing to do with it, but...)
When scraping, you might want to begin your scrapes up the fades a bit more, almost at the handle. If you start your scrapes at the same spot every time (at the fade), it's not hard to dig a groove there without noticing, which could easily become a hinge.
I also don't think that it's a good idea to start on one specific portion of the limb. I scrape the length of the limb until I see a stiff spot on the tree, then work a few scrapes in that area followed by a few more the length of the limb.