I agree with this, my blade will swing around backwards like that too (cutting edge facing back). I use it in that position to drag loose dirt smooth because it won't cut in. I don't have the scarifiers though. Now I wish mine did. Another welding project in the making...My guess (and it's just that) is you would pull the pin (red) the blade would pivot on the bolt (white) and the two pieces of frame would slide against each other (black) allowing the blade to spin on the frame (yellow). Note the pin holes on the opposite side of the plate from where it's currently pinned.
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