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Hello,

i have a question to the dimensions from nuts and bolts in the parts book.
What ist the difference between the Dimension MA and MB?
Ducati 4 speed monza/diana
8MA x 10,5 part nr. 0400.92.330 engine mount plate
8MB x 12 part nr. 0440.83.010 screw in the extra thread in frame

What material are the screws: steel is clear, what quality, what surface refinement?

Regards Karsten.

External threads are MA, internal threads are MB, if I remember right.
Rick

MA is standard metric coarse thread, 8mm is x 1.25 pitch
MB is metric fine thread, 8mm is x 1mm pitch

I wasn't really sure- found this in a book, but it may be a later standard than used in the 1960s.
Rick

Hello Rick, hello Jon,

after extensiv surching in my parts list i found some external threads with MA or MB dimension.
Thats why i agree with Jon - standard thread MA and fine thread MB.
Has anybody some ideas about the surface refinement.
I think zink plated, passivated or galvanised colorless

Karsten

Jon Pegler wrote:MA is standard metric coarse thread, 8mm is x 1.25 pitch. MB is metric fine thread, 8mm is x 1mm pitch

+1.

KarstenH wrote: Has anybody some ideas about the surface refinement. I think zink plated, passivated or galvanised colorless

The original finish was Cadmium plating. Depending on where you live, Cadmium can be difficult/expensive to get done these days. But Zinc is just as good (maybe try to avoid 'Bright Zinc', aka 'BZP').

Hi Karsten,

If you're referring to the original surface finish on the hardware, I believe they were cadmium plated.

- Jeff