My first week as a plumber my journeyman sent me to cut and thread pipe with measurements not end to end, but center to back, back to throat, back to end, center to center over a union with a 4" nipple, etc. A lesson learned hard, only later did I realize he was messing with me.
We ran gas line in a pipe chase in a school which was apparently against code. I was a one week apprentice but it was my fault. We ran it up the outside wall and across the ceiling.
