Date: Fri, 07 May 93 13:31:26 -0700
From: "David H. Wedeking" <davew@gandalf.ecb.tek.com>
I am still looking for a set of diagrams for head markings.
Try
Industrial Fastener Institute
1505 East Ohio Bldg.
1717 E. 9th St.
Cleveland, Ohio 44114
(This is a somewhat old address)
Report IFI-122 is entitled "North American Manufacturer Identification
Markings for Fasteners". I believe these folks have also contributed
to the publication of a world-wide listing of head markings, but I
don't have any details. Also, I believe the American Society of Mechanical
Engineers maintains a registration service for head markings and may
publish a list.
I have a document dated 5/10/90 which lists headmarkings known to have
been used on counterfeit bolts. Obviously this is pretty old, but (at
that time) it looks like most of the action was in Grade 8 and higher
fasteners. For Grade 5, it lists only unmarked bolts (just the three
lines), the Jinn Her company of Taiwan (a J in the center of the head
where the three lines converge), and the Kosaka Kogyo company of Japan
(KS in the center of the head). For Grade 8+ about 15 manufacturers
are listed. Apparently this list includes both questionable
manufacturers and honest ones who's headmarks have been imitated on
counterfeit bolts.
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