Don,
It has been a while since I sold my 112, which was the only scraper I
could ever get to work properly.  My fault, not the other scrapers.
Anyhow, I sharpened my 112 blade (which was an original Stanley) dead
straight and used no burr.  Angle didn't seem to matter.  That beauty
would take a beautiful thin shaving consistently on almost anything.
I always attributed my lack of success with other types of scrapers
with my lack of ability to turn a decent burr.  Another whole
discussion about which I have nothing to add....
Don't know if this will help, but might be worth a try.  Dead
straight, sharp edge.
Good luck.
Bruce Z.
Des Moines, IA