Are you sure that you moved the router in the correct direction?
Did you use a straight edge clamp as a guide or did you make a template to follow?
I like the template way for this and have made several. Since they require using a router bushing and following on the inside of the template (which is opposite from routing around the outside), I always mark an arrow on the template to remind me that it's an inside cut and needs to be routed in the opposite direction.
End grain routing is full of surprises. Even when doing it all correct, you can still make firewood very quickly. As the others suggested, see if you can make a wider groove or thin the board enough to save it. Figure out why it failed, and then do it a better way on the second try. In most cases, there are ways to save the piece. You just need to rethink your methods and what went wrong, then find a way out of the problem.
Central North Carolina
Last edited by CharleyL; 05-29-2018 at 04:13 PM.