If you carefully re-read Rick Dempster's post, you can see that he's
asking about the factory, stock tuning of an XB-40, not any retuned
variation. I've changed the subject of the post to help try and
eliminate the confusion.
Also, this is not about *how* it's done -- that part's been made
pretty clear -- but rather about *why* it's done, why there's a
difference between the depth of the bend on the lower blow E versus
the two upper ones.
In my offlist reply to Rick Dempster, I stated that I didn't even
know this was the case, despite the fact that I own one. Perhaps if
Rick Epping isn't here to offer an explanation, Winslow or another
XB-40 affecianado will help us out.
-tim