Actually the tear out occurs because the router lifts some of the end grain out of the wood. Depending on the wood type the length of the wood fibers can be short and when the router hits them they sort of flip out of the wood.pennview wrote:If you wish to prevent chip out or splintering when routing end grain on the butcher block top, you'll need to clamp a piece of wood to the outside edges of the stock to act as a sacrificial surface. You should have no problem routing the interior areas of the end grain of a butcher block style table top. It is only the edges where chipping or splintering is possible because the wood grain is not supported. That assumes that you're using a sharp router bit.
A plane can sometimes peel them out that is why I suggestted a belt sander.