I can almost believe it!
Back in the 70's when I did my electrical apprenticeship with a mining company, we had too spend some of our time in the with the fitters/machinists in the company machine shop, and were normally given the crap job too do.
One of these jobs was seating/bedding/matching up rotor for large air turbine winched (40hp motors). Anyway the procedure was bassically to put bearing blue on one rotor, assembly the motor, turn it over a few times, strip it and find the high spots on the teeth of the opposite rotor. You then filed the high spot with a very fine mill file and repeated the process until you had a good contact over the entire rotor "tooth". This took days at time too get a set of rotors matched. I was doing this job, and a new junior engineer came up too me saying it was too labour intensive, and rekoned that by putting find grinding paste in oil and feeding this through the motor would lap the rotors far quicker. So, being the apprentice I did this with his supervision. After several days, and untold sets of bearings we got nowhere. It all ended when the workshop engineer found out what was going on and procedded to rip shreds of the junior engineer for being so stupid.
Proof that even engineers have stupid ideas, but then we all know that from some of the wonderfull design feature on our bikes!
CJ