Shear may be added to most any punch (1/2″ or larger) to reduce the shock load on machine components and the punch and die, and increase their life expectancy. Shear, in essence, proportions the force through part of the stroke length of the ram – much less material is being cut at any one time than would be with a punch without shear.
THERE IS NO ADVANTAGE OF ADDING SHEAR TO SMALLER THAN 1/2″