Upgrading your plane with a Hock Blade? Add one of Hock's Chip Breakers for the ultimate plane blade tune-up! A plane's chip breaker (also called a back-iron or cap-iron) deflects shavings up and away from the cutting edge allowing the blade to shear the wood fibers before they lever up and tear out of the wood surface. This deflection also bends and breaks the shaving fibers so they can't lift and tear out ahead of the blade. The action of the chip breaker pressing against the blade at the thin cutting edge also strengthen the edge, reducing flex and chatter. Most standard chip breakers are only .065 to .070" thick -- too thin to add much strength. Hock Chip Breakers are .118" (3mm) thick for added mass, rigidity and support for the cutting edge.