The importance of using the correct fasteners in all areas of the machine is almost like an insurance policy. Threads will be accurate, nuts will be hardened and tempered correctly with the correct finish. In short, it would be unwise to say the least, to use anything other than the correctly specified fasteners like this 6mm Flange Nut.
Other 6mm Flange Nuts:
Please make sure part numbers ordered are compatible with your model. Use genuine OE fasteners. Why take the chance with any other type?