Perhaps Predator should have better quality control. Where are they made now? They say it a 17.75 mm shaft. Having been a machinist I still have my veneer and my micrometers. One shaft is 17.60 while the other is 17.50 meaning they're out of spec. They were out of spec when I first got them. I have cleaned them using McMagic from time to time. I can't believe I took that much off with the finest abrasive sheet of McMagic. Just saying.
You need a new set of measuring tools! 17.75 mm shaft?