I do. I actually mask the square BASE of the shifter boss. I see alot of frames painted where the painter only masked the cylindrical part, and not the base. Being a mechanic as well, I know that there is a little plate that goes onto the boss first. It has a square hole that fits over the square base of the boss. If there is paint on the square part of the boss, then the plate won't go on nearly as cleanly.
Sorry the 100k pics don't show details too well, but in the pic of the front end, you can kind of see the whole shift boss is white. (color of the first coat of primer)
I did! But there is tape covering the threads! And be sure to use blue (or green) painters tape, and
NOT the 99 cents-per-roll tan tape! I also tape inside the seat tube.
In the picture of the whole frame, you can see the white primer in the BB and the seattube.
The picture of the BB was taken before I unmasked it, the other two pics were after I removed the tape.
As a note, I sandblasted the frame lightly, including the BB & seattube. This cleans all the gook and crud from those areas. Then the primer is sprayed, including some in the seat tube & BB. The Mil thickness is not sufficient to cause problems in either area. THEN I mask all that needs masking and paint from there.
2nd note. This one makes me laugh! So I have to add my remedy. I dropped off a frame at a LBS to be built. I had apparently forgotten to unmask the seattube. The guys at the shop said they spent HOURS trying to get the tape out!
Sooo, to GET the tape out. I use a #11 Xacto blade to carefully get under the edge of the tape at the seat collar. Then, take a longish pair of tweezers and slide one leg between the tape and the seat tube. Push that leg in carefully as far as you can get it. Now just twist the tweezers like you would open a can of sardines. The tape rolls right around the tweezers and comes out in one piece.