On Sat, 9 Mar 2019 02:19:11 +0000 (UTC), Cydrome Leader
wrote:

How common is this- inch threaded fasteners with metric grades stamped on
the head?

Came across some "12.9" stamped allen head bolts with a real 5/16-18
thread. Does anybody in Taiwan ever stamp grade the grade 5 or grade 8
lines on metric fasteners?


A class 12.9 bolt is described as being "alloy steel quenched and
tempered" and has a minimum tensile strength of 1220 MPa, which is
about 176,946 psi.


--
Cheers,
John B.