mil spec bolt headstamp question

[Jim Burns]

While cleaning out a machine storage building we've discovered several
pallets of mil spec bolts and steel stop nuts. They are obviously old
aircraft military surplus, they are wrapped and boxed like only the military
would require. Most are cad plated, either gold or silver. The bolts have
head stamps of "A" and "L". The boxes seem to have mil spec identifications
other than AN, NA, or MS part numbers. Does anybody know what this head
stamp designation signifies?

I'm sure we'll just end up using them around the farm, but I'm curious as to
their specs.

Thanks
Jim

[George Patterson]

Jim Burns wrote:
> While cleaning out a machine storage building we've discovered several
> pallets of mil spec bolts and steel stop nuts. They are obviously old
> aircraft military surplus, they are wrapped and boxed like only the military
> would require. Most are cad plated, either gold or silver. The bolts have
> head stamps of "A" and "L". The boxes seem to have mil spec identifications
> other than AN, NA, or MS part numbers. Does anybody know what this head
> stamp designation signifies?

Probably nothing. It may be an indicator of the manufacturer, or the "L" you're
seeing may be a stylized "N" (the resulting mark being "A N"). What's more
important is other markings on the head. A standard steel aviation grade bolt
will have a cross or asterisk in the center of the head. If an asterisk, the
legs will probably be pretty long, giving the effect of an "X" with a line
through it. Stainless steel bolts will have a single raised dash to one side of
the head. Aluminum bolts will have two raised dashes on opposite sides of the
head. A bolt with a circle around the asterisk is a reworked bolt. A bolt with
an "X" to one side of the head is a special purpose bolt. There are a few other
markings that indicate special purposes or inspection stati.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.

[Jim Burns]

Thanks George,
I found some completely packaged boxes in another wooden crate, these boxes
have the MS part number on them, but the bolts only markings are the A or
the L, non of the other markings. It "looks" like they are a manufacturer's
designation because they each match up with the first letter of the
companies names that are on the boxes. At least I know what some of them
are now.
Jim

[George Patterson]

Jim Burns wrote:
>
> I found some completely packaged boxes in another wooden crate, these boxes
> have the MS part number on them, but the bolts only markings are the A or
> the L, non of the other markings.

In the AN world, having no hash marks on the head indicates low-strength steel.
Now, my info is coming from an elderly copy of AC 43.13-1A. Perhaps your bolts
predate the adoption of that marking scheme.

George Patterson
Why do men's hearts beat faster, knees get weak, throats become dry,
and they think irrationally when a woman wears leather clothing?
Because she smells like a new truck.