1924 gearstick

Unknown

Have almost recond my gearbox and Im working on the gear stick. On the large round part that goes in the top of the gear box, where the 2 & 1/2" x 1/4 diam pin goes, there is a 1/2" hole on one side and a machined slot for a 3/8" square nut with no thread on the other side. Seems strange to me that you put a 1/4" pin through a 1/2" hole and then through a 3/8" nut. I'm curious so I welcome any comments. Is this what other makes do as well? Barry