Loose Bosses by Dave Taylor
This is the best way to tighten loose bosses. You need a
heavy engineers vice, a 3/8" steel ball and a scrap length of screwed
rod. If the vice jaws are serrated you will need a smooth flat steel plate.
1. insert the ball into the peened side of the boss.
2. clamp in the vice and tighten just enough to tighten the boss.
The screwed rod should be run through both boss tappings before this operation to avoid distorting the tapped holes. The flat plate (if necessary) is inserted between the vice jaw and the flat end of the boss to protect it from damage.
This method is permanent and invisible and can be used on any standard type of boss.
NEVER use a hammer!
Dave Taylor. Copied from spanner.