Explanation: From the context, the spindle has a flat side (to stop something from turning). If the washer is too thick, the blade is moved away from its correct position, and can come into contact with the flat side of the spindle. If you have a drawing or picture, you can probably see what is meant.
"Getriebe-Abtriebswelle mit Anflachung ... Shaft end with flat..."
Explanation: From the context, the spindle has a flat side (to stop something from turning). If the washer is too thick, the blade is moved away from its correct position, and can come into contact with the flat side of the spindle. If you have a drawing or picture, you can probably see what is meant.
"Getriebe-Abtriebswelle mit Anflachung ... Shaft end with flat..."