Are most frames compatible with different brands of machines?
No. Most frames are machine-head specific since they require a carriage that fits both head and frame. AFAIK, currently only Grace sells carriages for some other brands. I believe Juki sold a carriage to turn their 2200 (I think that was the number - not a TL but a larger machine) sit down into a frame machine.
I have a sit down mid arm that I had hoped to use with a frame. As you can probably tell I don’t know anything about this. I have used the sit down successfully but I’m starting to have problems with my hands. Is finding a frame for it unrealistic?
What brand mid arm?