Just posted an auction on ebay for 10 Gibraltar tension rods with built in washers. I know they're not vintage but they will work will vintage drums like LUDWIG.

https://www.ebay.com/itm/10-Gibraltar-Tension-Rods-with-Built-In-Washers/264239474411?hash=item3d85e666eb:g:P40AAOSwoSNcittB