What would you tip a table mechanic?

9BallPaul · 2011-01-15T02:56:09+00:00

Recently I sold my house and table, and bought a better table that I improved with Simonis and Artemis rails, 4.5-inch pockets. The mechanics did a superb job, took about three hours and promised to return for free if leveling problems developed. Hasn't happend. Recently I dropped off an envelope for them at my table dealer's store. The table was an 8-foot Kasson, and it plays terrific. What was an appropriate tip?