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.
Proper operation of a machine requires two further considerations. Most of all is proper lubrication, but also maintaining cleanliness is critical. For blades to perform well they must remain clean, it is natural for blades to get a little gritty in certain areas, near the back it is common to run across dirt and alfalfa debris, this will dry out a blade and dull it quickly. The undercarriage is also a problem area due to lanolin and debris. In these areas, I try to be especially conscious of blade cleanliness and lubrication. It will slow a machine down and wear blades out running through this stuff and the time saved taking the time to stop and clean off / oil the blades is well worth the delay.
The blades above can be purchased from Amazon here: