After a horse is Shod the hoof will continue to grow. After some growth it becomes necessary to pull the shoe, trim the hoof, & re-apply the shoe. Every reference I have ever seen re Stub Twist/Damascus indicated these "Pulled" stubs were used. Reference was made to the fact the iron had been compacted by the impact of the horse's hoof. Greener even insinuated (Which I would find exrtemely doubtful) that the stubs "Absorbed" carbon by virtue of this pounding within the hoof. All of this describes a nail which was "Worn" by the horse.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra