I've got a few golf ball handles. They do work, I like them on smaller files, not so much on bigger ones. They don't fit in drawers, where I store most of my files. I turned some nice wood handles years ago with copper ferrules. Always wanted to make a bunch more someday, but just never got around to it. The last couple file handles i made I simply drilled chunks of hardwood pallet, pounded them on and then shaped them on the disc sander with flats, not round. Some with 5, some 6, some 8. They were actually very comfortable to use, and very quick to make.
I'm always torn between taking the time to make nice things, and just making things quick to get it done and over with. The pallet wood was a done and over with decision, but they turned out pretty nice and functional it makes me just want to do that from now on....
I actually use a lot of files without handles....gasp....ya I know, judge me....
. Not on a lathe though, never on a lathe. But for hand work, sure. I preferred them mostly handless because they fit in my toolbox drawers better, and using them flat to deburr plates was handy and something I did a lot. But my most frequent users all had handles. If I ever get a nice bench space to work at, with room for a big file rack, I will put handles on the entire drawer full.
I think that's the most words I ever wrote about file handles lol.