Showerthought: I spent 3 months trying to find a replacement part for my grandfather's old slide rule
I wanted to fix his 1950s Keuffel & Esser model for a display case. The tiny brass cursor was bent and I thought it would be a quick online order. After checking every antique shop in Cleveland and posting on five different forums, a retired engineer in Oregon mailed me one from his own collection. Has anyone else had to hunt down parts for old calculating tools?
Check those old engineering forums, they're full of guys who just want to see this stuff saved. Like @the_thea asked, a lot of times they'll just send the part for free if you cover the postage, especially if it's for a family piece. I had to do the same for a broken spring in a vintage adding machine. The key is to be clear it's for repair, not resale, and offer to pay upfront. Those small communities really come through when you hit a dead end with regular shops.