Perhaps the one subject that I found most difficult to learn about was blade set-up and alignment. There is precious little out there on proper blade set-up and operation. Once you start out shearing you will learn just how important this is, – while it is inevitable that you will nick and cut sheep, a great deal of that inevitability rests upon proper blade set-up.
First set of pictures below shows the two elements of a blade:
The second picture set shows the proper relationship they must maintain to safely shear an animal.
While it is true that the closer the cutter is to the bevel (brim where it slopes off) the better the machine will cut, it is equally true the risk to the animal greatly increases. At all times the cutter should remain approximately 2 mm or .07 inches (5/64) from the bevel edge. Otherwise, not only the risk of cuts greater, they can be far more severe, especially in critical areas like nipples, narrow angles (tendons, folds, wrinkles) and tails.