You’d hope the original owner would tape a key inside each file cabinet before donating it to charity; ours arrived unlocked and without keys. Fortunately, eBay sellers have All The Keys and I ordered replacement keys for each cabinet.
One pair of new keys fit into their lock, but the shoulder didn’t seat properly and the key didn’t turn:
Compared with a key for the other cabinet (on the bottom), it seems the tip profile wasn’t quite the same:
Perhaps the underside of the tip hadn’t been cut? Stacking the two keys makes it even more obvious:
The eBay seller suggested the lock cores have changed over the years, as other (unaltered) keys fit current cabinet locks. Perhaps HON used fussy high-quality lock cores back in 2004 when they built these cabinets.
I gingerly filed the 125E key’s tip to match the 101E key and, after several iterations, the shoulder seated firmly in the lock and the core turned smoothly. Flushed with success, I marked the other key of the pair, filed to the mark, and it worked on the first try.
Mary doesn’t plan to store any secret fabrics in her new cabinets, but now I can declare victory and move on.