I like finding stuff in the disposal units myself.
You wouldn't believe the nice mattress I got one time. Other than a couple of yellow marks on it, you could hardly tell it was used.
Considering that you have a propensity for piecing together nice little repair and finishing
lathes from odds and ends, there is no doubt that within a couple of months, you will posting pics of something very functional that you built with these.
There was some pics posted a few years ago of a Panto Graph with rails like that. I don't know if Joe B built and sold those ones but I believe it was purchased from him. So, a Panto might be one option.