The item under consideration is an idler pin constructed of cold drawn medium carbon steel. The pin is not threaded, measures approximately 3.25 inches in length and 1.125 inches in diameter and has drilled holes on the shaft for lubrication. The idler pin is a replaceable component that is cold pressed into the pump head. It functions to hold the idler gear assembly in place and connects that assembly to the pump head. The idler gear rotates on the pin, but the pin itself is not a moving component of the pump, has no direct role in displacing fluid, and is not capable of transferring power.
[1] Please importantly note that only the relevant portion of the related is displayed above. You may refer to the said customs ruling for the entire ruling explanation.
[1]. https://rulings.cbp.gov/ruling/N323952