Dave,

It could be that a DC motor and a 555 timer circuit with a pot to set the time and a button to trigger the process would do the job. Some of the timer circuits on eBay have on board pots, so all you would need then is a trigger and a latching relay. The latch would switch the motor on and after a preset time it all drops out waiting for the next trigger.

As you say, accuracy to CNC standards is not the issue.

I use a similar circuit to hold off a pump for 7 seconds, otherwise the relay would be switching the pump on and off all the time as soon as the reservoir fluid level drops below the float switch.

Cheers,

Rob