The basic habit of careful machining: rough to within a few thou, then take light cuts and measure after each one until the size is reached. It accounts for tool deflection, springback and machine backlash that the dial does not show. It costs time, but taking a little more off is always possible, and putting it back is not.
Don't try to hit the bore in one pass, sneak up on it, two thou at a time, and mic it every pass.
Also heard as
- sneak up
- creep up on it
Related terms
Spring pass
A repeat finishing pass at the same setting to remove the material left behind by tool spring.
Skim cut
A very light cut that just cleans up a surface or establishes size without removing much material.
Kentucky windage
Adjusting by experience and feel rather than by the numbers, borrowed from riflemen aiming off for wind.
Mic
Short for micrometer, pronounced mike, and the verb for measuring a part with one.