MRC Forum- brought to you by www.morini-riders-club.com Member: g7AW3f

I have been translating a parts manual into English (MS word online does the translation!) for a friend with a Morini 175 GT (a very early one I believe). The Machine screw sizes are MA. I guess the M is metric, I wondered what the A stood for?

Hi Richard.

The following is a Google translation of a snippet from the Sapienza University of Rome website...

"The unification of the threads underwent a notable increase after 1964 transformation. Before that date, the threads, despite being metric, did distinguished into 5 series: MA, MB, MC, MD, ME.

The MA thread has been replaced by the coarse thread,the other 4 (MB, MC, MD, ME) in a single fine pitch thread series".

So it would appear that 'MA' is an obsolete designation for a common or garden Metric Coarse thread. The letter 'A' doesn't really stand for anything.

Many thanks for that. Your Googling abilities have surpassed mine!

Thanks Richard. Although I think I probably need to get out more.