Story: Bought a 1905 treadle machine and nice cabinet a few months ago. The shuttle for the bobbin was missing, but you can buy a newly made replacement for 39$ online. So I got the machine, spent 2 days cleaning it up so it was smoothly running and clean. Ordered the shuttle for 39$ and a pack of long bobbins to fit it.
Got shuttle and bobbins in the mail Wednesday. Mucked with the machine all evening after work Thursday night. However, I can't bring up the bobbin thread no matter what I do. Finally decided the bobbin and shuttle, despite being advertised as the right thing, were sized ever so slightly different than what the machine needed. No matter. Contacted the company I bought them from, and while they swear it's the correct replacement part, they'll refund me.
Find an 1892 same model machine on Craigslist with a bobbin and shuttle for 30$ in the next town over. Purchased it after work for parts since apparently that's the cheapest way to go. It's all rusty and doesn't move smoothly at all. Brought it home, removed the shuttle and bobbin, discover it's the same bobbin size as came with my machine as suspected, and started mucking with my 1905 machine and the 1892 shuttle. A few hours later, and almost completely out of my mind at this time because it's still not working, I decide to stick the 1892 bobbin and shuttle in the 1892 machine. Thread comes right up first time, machine starts stitching. Granted the stitches were all kinds of messed up due to not having the tension right... but it works.
Irony: 1892 uncleaned machine works better than 1902 machine that I spent 2 days cleaning and oiling and hours messing with. Now I have to spend probably more time cleaning and oiling the 1892 machine to replace it in the sewing cabinet to be able to use it.