ferrule, butt end
鐓 centers on the metal cap or ring at the end of a tool handle or weapon shaft: a ferrule, or the butt end itself. Both given meanings describe the same protective or finishing metal piece.
鐓 combines 金 (metal) with 敦, which likely contributes the sound. The character is used for a metal ferrule or butt end, but its detailed historical development is uncertain.
The left side is metal 金, and the right side 敦 looks like a sturdy cap being hammered onto the end of a handle. Picture a metal ferrule protecting the butt end of a spear.
For タイ, imagine tying a metal ferrule tightly onto the butt end: tie -> タイ, and the metal cap is secured.