Part of a Valve for air or gas or steam?
The tapered tip is for a nonslip if a bolt is to to secure something with a tapered hole for it to be run home in.
But yours is designed (due to T-handle) for opening and closing to adjust more than only during initial positioning for metering something.
A pressure lantern for example has a similar shaped rod but with a wheel attached to turn it.
Your piece has the nonthreaded area for a packing seal but no manner of securing it.
That doesn't mean it didn't have a nut over it.