Before I got my first fiberglass pole, I vaulted 10-6 with a 10-0 steel pole (in 1965).
This was a 14 inch handstand! Not much of a grip, and not much of a handstand for an elite vaulter, but I was only 16 years old at the time.
In fact, there were two other vaulters in my local area that vaulted higher than me that year (also both on steel poles).
I didn't realize it at the time, but in hindsight, that was probably the best way I could have learned how to swing on a pole!
Kirk