Need an ID and/or place to find this hardware

A bit of help requested. This hardware is used to hold the screen window insert into an older screen door—you turn them to release the window and swap in a glass insert. They are set into a 1-3/4 inch drilled pocket in the door frame.

Does anyone know what they are called (so I can google them) and/or where to get them? I need a half dozen or so. I have checked a couple of hardware stores, Home Depot—the older guys recognize them but don’t know where to get them.

Matthew—Thanks in advance!