Hi Olivier
½" and 13mm ribbons are totally interchangeable. There is only 0.3mm (0.012") difference if there is actually a difference. The USA still works on the Imperial system, so anything close to ½" is called ½". Europe has been metric for a long time, so feet and inches are all but forgotten. If you measure the distance between the flanges on a standard 2" (51mm) ribbon spool, you'll find that it's actually 14mm for a little clearance.
It's not until you start getting into the 7/16" (11mm) or the 9/16" (14.3mm) ribbons that you may run into problems with ribbon feed or print quality. At the moment, I'm running a 9/16" ribbon in an Olympia SM-7 with italic typeface. When I load the machine with ½" ribbon some of the upper case letters get their tops cut off on the paper. Hope this helps,
Sky
We humans go through many computers in our lives, but in their lives, typewriters go through many of us.
In that way, they’re like violins, like ancestral swords. So I use mine with honor and treat them with respect.
I try to leave them in better condition than I met them. I am not their first user, nor will I be their last.
Frederic S. Durbin. (Typewriter mania and the modern writer)
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