See the picture, taken from an online review. My question is specifically about the arbor size. The review says it has a 3/8 arbor flanged to 1/2 inch and 20 mm. Now there's quite a difference between 1/2 inch and 20 mm. I was thinking it meant the stabilizing washers were reversible or something. I took my blade off and I don't see how you could use a 20 mm blade without an adapter. Am I missing something?