Growing up my mother was really into using the phone. Our landline was always connected to someone and my mother chattering. My mom got a fancy white dial pad based wall mounted phone and an extra long phone cord so she could talk on it access the kitchen.
I don’t think we had a rotary but my grandmother did have a light green rotary in the basement for a period
My parents house has/had the same thing! It was always super useful during blackouts because it didn’t require power like the wireless phones did with their base unit. Still functions!
Contract a shop with a Swiss lathe. Have them turn a rod to a specified axle diameter and then thread both ends at a smaller diameter. Use the shoulders where the threads meet the middle to set your gap.
You’ll need to see what they might charge for a whole bunch of them because a small quantity won’t be cheap. I could cut the things pretty easy as a prototype kind of thing, but it would NOT be cost effective for production because I wouldn’t be able to run them quickly enough.