CrayfishYAY, nice idea to carve a stamp for your letterbox! However, there is no requirement that you have to provide an ink pad in a letterbox cache. In fact, an ink pad in the cache container can over time cause problems, such as staining other objects in the cache, the pad dries out, etc. In the descriptions for the letterbox caches that I have placed, I mention that there is no ink pad in the container and that geocachers that want to stamp their book should bring their own ink pad. So far no-one has complained about missing ink pads.