i have no idea what it is but i will add in my 2 cents any way ,,lol
when i first seen the picture i thought it looks like a Knob Handle , i have some that are new items less then a year old used on Nautilus weight benches , now i am not saying that is what this item is ,, i was just surprised at the resemblance is all .
i will take a picture in 5 mins and post it so you can see what i am saying.
Now i am not a expert and all i go by is what i have seen in my life dealing with antique structures and the implements found in and around them , some from that era and some not , plus growing up in a time where you had to have knowledge in alot of areas to do alot of things . to me the ridges look to perfect to be wore down , it looks to me they were made the shape they are now .
and ty to BigC , i had never seen horn caps ( what we called them on the farm ) that had holes all the way thru them , ours were brass balls and had 1 hole for the horn to go in, but i do not think this is horn decorations either .
the closest ID i liked and agree that if Cannon says it is not artillary related then its not , but the idea if a wooden handle /pole goign thru the tapered hole and having a wedge driven thru the split end like a old hammer or axe makes sense to me,, now what was it used for ? no idea..lol