When the parts are rejected or the gages or instruments are giving dodgy answers the red flag goes up and panic usually ensues. Everyone involved defends their turf, talent or toys which is normal but rarely answers the question of what’s gone wrong.
We are frequently asked for help in such situations and as is often the case, a fresh set of eyes looking at the problem can be of benefit. I thought it might be useful for readers to have a checklist of sorts so they can narrow their focus to get to the cause of the problem from a measurement point of view. Everyone wants an app for everything but they are not always forthcoming or workable. However, the 4-M rule can be used to keep you on track.