They have got to be at least 40 years old.

Have a plastic threaded dowel to assemble pieces together end to end
to get whatever length you need.

My mother still had some when I closed up her place in 2007.

She was in Apple Creek area (30 miles west of Canton)

I'd start with Lehman hd'we in Kidron or maybe a Farm & Fleet type
store.

Check the hd'we stores that serve the Amish like Lehman above.

Have fun.
Lew


Thanks for showing my age ... LOL. Yeah, they close to that age. I
remember my dad making a set for my brother's new home just after he
got married and that is over 25 years ago. I have looked in Home
Depot, Lowe's, 84 Lumber, and other local stores but have not seen
them in years myself. With all the DiY stuff out today, I'm surprised
not to see them back in stores. You've given me a few other ideas of
where to check, so I'll keep looking. I've thought about turning some
myself, but it would take forever to make enough on my mini lathe to
do the shelving system I have in mind. Anyway, thanks for the reply!
`Casper