Submitted as a historical curiosity, but one that actually works. Correction to title: it's actually aluminum oxide, not silicon carbide (aka carborundum). Since most of us have obsolete, semi-obsolete or rare shaving oddities laying around - gimmicky razors, useless stroppers, one-of-a-kinds, etc - I think a Museum of Shaving Paraphernalia type thread would be neat to look at.
I imagine there were several versions of this back in the day. I pulled it out of storage to keep track of how many shaves I can get out of the Segal w/Shaeffer blades.
Only as an experiment over Christmas break. I have no intention of doing all 20 Shaeffers or any others.