Of the hours your shop was open, how many was the spindle cutting?

A CNC machine has one number that matters — how many hours it was cutting metal.

Most job shops know how many hours the shop was open. Very few know how many of those the spindle was actually running, because nothing separates cutting from setup, from waiting, from standing idle.

Each state is recorded by the operator on the same screen he already uses to move the job.

The first part off a new setup must be checked before the run continues. Correct, and non-negotiable.

But the machine stands still while the inspector is somewhere else, and nobody counts that wait because it is treated as part of setup rather than as a queue.

The first-off request appears on the inspector queue the moment the part is off, ordered by how long each has waited.

An insert has a life. Run it too long and you get a dimension drift that shows up as a rejection twenty parts later.

Tool changes happen by feel and experience, which works until the experienced person is on leave. Nothing records how many parts a tool actually ran.

Parts produced are counted against the tool, so a change is due at a number rather than at a hunch.