--- In csshlhunley@yahoogroups.com, "messerrt" <messerrt@a...> wrote:
> Thanks Michael, I have seen other rivet photos that didn't have
such
> a clear view of the countersink profile. I have created a drawing
of
> the rivet based on the idea that the hull plate is 3/8" thick and
the
> backing ring is 3/8". The rivet looks to be 1" dia. I will post
> the .bmp image in "rivet size" folder.

Robin:
Not disputing your analysis of the but offering a different opinion,
I've posted three more pictures in the Files rivet folder. The
pictures illustrate how I've used CorelDraw to estimate sizes. As
always with this type of guess there are a lot of IFs.

Working from the exterior photo with the rule, I see three possible
circles. The two larger ones pass or come close to the edge of the
panel, so the smallest seems most likely - ~0.76" (see River
tail.jpeg).

Using the artifact photos and presuming the large button is quarter
sized, the head size appears to be on the order of 0.78" and the
shank about half an inch (see Rivet head.jpeg).

Finally, using a photo of the center hull opening that I know from
other sources to be 30" wide I estimate the rivet holes to be
approximately 0.73" (see Rivet holes.jpeg).

Putting this all together I offer a head size probably less than an
inch, maybe close to my 7/8". The tails size might be a bit larger,
especially if the tails were hammered down to flatten them, but still
less than an inch. The shank was less than 3/4 inch and perhaps 5/8
inch.

For what it's worth.

Michael