I have double-hung wood windows on my house circa ~ 1950. There is a part that screws to the frame that holds the storm window in place. One end of it broke, so I need to replace the part. I've been to all the popular hardware stores in my area (Home Depot, Menards, Lowes), and a couple local shops. No one has it, much less knows what it is called. It's aluminum, and has a plastic piece on each end that the storm window slides on. For the lack of a better term, I would call this thing a tension spring. It basically holds the sliding storm window against the other screen/storm window.
#1) What is this part called?
#2) Any suggestions where it can be found?
Thanks in advance for the help anyone can offer. I'm stumped.
Images below. The part is originally bare aluminum; it's painted brown in these photos.