My axle is just resting on a $16 Harbor Freight furniture dolly. Serves it's purpose, and the more I think about it, seems just as well to use it for paint. I could strap the axle to my engine hoist, but either way I have to hit what I missed following assembly.
Unless talked out of it, I plan on using sponge rollers anyway, so touch up is easy. Same on the frame, using MasterSeries and their satin top coat....................I've read it comes out real nice with a sponges. If I understand it right, the results are even better than through a gun, though I'm not sure that includes the top-coat. Masters recommends sponges for the primer coats.
I'm looking for a real nice finish to go with a un-pitted & blocked frame. I'm good with a brush, but I don't know, perhaps the top coat through a gun will look cleaner.
Here's someone's frame with MasterSeries. Can't say if brushed or sprayed.
https://s20.postimg.org/8wszjd6p9/image.jpg
Other than that, how have you painted an axle, or frame?