Hammer handles are a consumable item. Rehandling your hammer will likely need to be done at some point.

these are the hammer handles that are designed to fit my hammer eye. However Each hammer eye is slightly different for the given weight so they still need to be fitted.
Hickory hammer handle 16” long 

All hammer handles require fitting to the hammer head. 

here is a video of how to reset the handle if it begins to come loose but didn’t need replacement yet.

https://youtu.be/7QjMHE-KSzY