-----Original Message-----
From: David Soderblom <drs@...>
To: STMFC@...
Sent: Fri, 22 Apr 2005 13:04:12 -0400
Subject: [STMFC] Carriage bolt heads



There are also "carriage" bolts with conical heads specifically for
flat car decks, and I have seen such on an EJ&E 70-ton flat. These
allowed for a fully flush surface.

David Soderblom
Baltimore MD

On 2005 Apr 22, , at 04:14, STMFC@... wrote:

Message: 5
Date: Thu, 21 Apr 2005 23:53:50 -0500
From: "Tom Jones III" <tomtherailnut@...>
Subject: Re: DRGW 6500 series flat

"Carriage bolts" is the correct term for bolts that have a rounded
head with
a small square boss below the head at the top of the bolt
shaft/threads. The
top of the bolt indeed looks like a rivet driven through the wood.
Carriage
bolts are very commonly used to bolt down wood to metal structures,
much
more so than standard hex head or square head bolts. This is because
the
bolts do not prove to be a snag to loads, and because only one person
is
needed to install them, as the square boss below the bolt head catches
in
the wood and keeps the bolt from spinning while tightening. Rivets
would
almost never be used to hold wood to a structure, as wood simply cannot
stand the riveting process without splitting, and once driven, a rivet
is
not replaceable, but wood does wear out rapidly.

Carriage bolts were originally used for bolting together the frames and
structures on carriages, hence their name. They are very nice looking
when
installed on an exposed surface, such as one might find on a wagon,
etc.
They would be only slightly exposed on a flat car deck, and because
loads
would tend to wear them on the tops, rust and other weathering would be
common after only a few uses of the car.

Tom Jones III

David Soderblom
Operations and Data Management Division
Space Telescope Science Institute





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