Pre-ISO Metric Fasteners
Pre-ISO Metric Fasteners
(OP)
I seem to recall that prior to ISO standards, the Japanese had their own standards for metric fastener sizes. Many of these became obsolete when metric ISO fastener standards were adopted. I am right on this? The reason I ask is that I have run across some fasteners on a Japanese 2 stroke engine (1980 vintage)that appear to be 5.5mm with a .9mm pitch (they could also be 12-28).





RE: Pre-ISO Metric Fasteners
I think that the thread diameter and pitch matches ISO, but that for some sizes the wrench hex was different.
RE: Pre-ISO Metric Fasteners