Thanks for all the answers. I measured, sure enough, 20" is the limit. They just stopped and added a strip to make up the rest.
All I need to make the snare work is the screw, lock washer and a nut, and then a knurled thumb screw or knob. I kind of expected to find parts, inside the drum. Nothing. So someone "cleaned" it and removed the rattles.
Still looking for the invisible vent, any badge or Mfg. ID? The feet and the bottom head, which really is calf BTW, and the answers here have me convinced it's Slingerland. Just mystified by no markings. What were they, the secret drum company?
I hope this doesn't offend anyone but it's making a dandy night stand right now. LoLoLoLo
Hey I could furnish my whole living room with drums as everything except the chairs and couch. TV stands, end tables, coffee table. Hmmm ???