Current Custom Bach Project, begin date: 02-08-03
It's very important to work slowly and carefully. Though the removal of metal is rather slow, you wouldn't want to cut too fast and end up with a smaller gap. You can't put back the metal you've cut away!
I make several rotations, then check the measurement with the mouthpiece in place. Before inserting the mouthpiece, it's best to use a clean, dry bristle brush to remove the small brass shavings. You wouldn't want to scratch the shank of the mouthpiece!
Eventually I'll end up with just the right amount of gap. Like I said earlier, the standard gap is .125". Some people like to have shorter distance, while others prefer a longer gap.