[macdonge]

One additional point regarding use of the outside micrometer in the first step of the procedure - this is simply intended to get you started in the right direction (i.e. determining where to start tapping) or confirm during the process that you aren't going in entirely the wrong direction. In between, you'll mostly be going by feel and the indications witness marks may provide after each set of 'whacks' with the hammer & trial fittings.