A question about thread sizes in a parts catalogue
- Parker3865
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A question about thread sizes in a parts catalogue
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?
Morini 250 2c rebuilt from a box of bits.
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Re: A question about thread sizes in a parts catalogue
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The MA thread has been replaced by the coarse thread,the other 4 (MB, MC, MD, ME) in a single fine pitch thread series".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.
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The MA thread has been replaced by the coarse thread,the other 4 (MB, MC, MD, ME) in a single fine pitch thread series".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.
- Parker3865
- Posts: 145
- Joined: 13 Sep 2022 18:16
- Location: Brentwood
- Contact:
Re: A question about thread sizes in a parts catalogue
Many thanks for that. Your Googling abilities have surpassed mine!
Morini 250 2c rebuilt from a box of bits.
-
- Posts: 104
- Joined: 12 Jun 2022 18:49
- Location: Warwickshire U.K.
Re: A question about thread sizes in a parts catalogue
Thanks Richard. Although I think I probably need to get out more.