I learned early on that you should never let a bit bottom out in the router. That’s because tightening the collet nut tends to force the bit deeper, so you need to provide some room for the bit to move or you won’t be able to snug it properly.
When you can lay a router on its side, the procedure is fairly easy. But when you’re changing bits in a router table, it’s easy to run out of hands.I solve the problem by dropping a single Space Ball down the router’s collet. (You usually use these .026"-dia. resilient spheres along the edge of solid-wood door panels to prevent rattling and to accommodate seasonal wood movement without cracking.) I can then drop the end of the bit right onto the ball and tighten the nut. The rubber easily compresses under the pressure, allowing the collet to fully tighten.