Re: Carriage bolt heads


railsnw1 <railsnw@...>
 

The flat head style carriage bolts are generally known as elevator
bolts. Some of these have the square shank like a carriage bolt but
other have an all round shank with a slot in the top to hold it with
a screwdriver as it is tightened. Northern Pacific war emergency
boxcar NP 28129 has these slotted style to hold down the running
boards. I know as I'm currently removing nearly 100 of them so the
wood running boards can be replaced.

Richard

--- In STMFC@..., David Soderblom <drs@s...> wrote:
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@c...>
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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