[TheForge] nail header

Sun Jul 4 16:00:11 EDT 2004

Clearly I have not be clear in my explanation of what the nail looks like.

First what do we mean by shouldering the nail stock or rod -- historically
most of the rod was approx. square in cross section because in was cut from
thin bar in a slitting mill.  Slitting mills predate the early use of flat
rolling mills for making sheet and plate.  On the edge of the anvil the
stock was reduced in size to a smaller square section than the parent rod
itself.  Just like you were putting a long tenon on the end of the rod.

The last portion of this square section (farthest from what will be the
head) is taper to a blunt point.  The long square section of the is
typically about 1/2 the size of the parent rod (or 1/4 of the area).  Since
volume is preserved in forging (except for scale loss) this section of the
nail will be somewhat greater that 4 times the length of the material first
placed on the anvil for shouldering (or forming a tenon).  The somewhat
greater being cause by the length of the taper to the point. If I am using
1/4 inch by 1/4 inch stock and placed 1/2 inch of stock on the anvil,
shouldered it and then draw it out to half of the parent bar (both thickness
and width -- 1/8 x 1/8) it would be 2 inches long and a little bit more
because of the taper to a point..

If instead of shouldering we took the same amount of starting stock and
taper it -- how long would the taper be?  The volume of a pyramid is equal
to 1/3 of the height times the area of the base.  So if I start with the
same amount of metal 1/4 x 1/4 by 1/2 inch long and taper to a perfect
pyramid -- the it will be 3 times longer or 1 and 1/2 inches.  Same volume
of metal but a shorter nail.

To make a nail the same length using the pyramid -- will require more
metal -- which is how we started this discussion.

Now to the more important point for us today. (our metal is cheap compared
to the wrought iron of the early 1800's.)

Mike Spenser said

"I never did get nail making to work right.  What is this "comes out of
the header very easily" of which you speak? :-) I'm going to have to
go out and try to put this discussion and this impromtu review of my
nail collection [2] to practical use."

Shouldering makes the nail come out of the header much more easily -- 
because having the shoulder gives something to support the material which
will be forged into the head rather than supporting it with the taper of the
pyramid.  Less material wants to be upset (or extruded) into the header with
the shoulder and it is this upsetting (extruding) of material that makes the
nail want to stick.

And thanks Mike for the data on the historical nails from your place.

Now if I could just have the hammer control to do the shouldering -- 
it is a lot easier to do the math and the solid geometry :-)

Dave Smucker

----- Original Message ----- 
From: "Michael H. Murphy" <blacksmith at comcast.net>
To: "'Sponsored by ABANA'" <theforge at mailman.qth.net>
Sent: Sunday, July 04, 2004 11:46 AM
Subject: RE: [TheForge] nail header

> Sorry, Dave.  Solid geometry and mathematics are against you on this one.
> Assuming the heads are the same size, let's just look at the shank.  A
nail
> that is 2" long and tapered its whole length will occupy less volume than
a
> 2" nail that is the same thickness for 1.5" and then tapered for that last
> 1/8".  I can show you the math, but we'd better do it offline; there are
> some graphics that go with it.
>
> Murf
>
> > -----Original Message-----
> > From: theforge-bounces at mailman.qth.net [mailto:theforge-
> > bounces at mailman.qth.net] On Behalf Of David E. Smucker
> > Sent: Saturday, July 03, 2004 9:14 PM
> > To: Sponsored by ABANA
> > Subject: Re: [TheForge] nail header
> >
> > The volume of total metal in the nail is less.  I happen to have one of
> > Jerry Darnell's nails in front of me and while the shank is taper to a
> > blunt
> > point it is really quite rectangular except for the last 1/8 of an inch
> > just
> > below the head.  This short section is upset to the size of the header
> > from
> > forming the head.  The rest of the shank is the size that the nail was
> > formed to before going into the header.  In other words with the
> > shouldering
> > the nail is a very loose fit going into the header.  This also means
that
> > the nail comes out of the header very easily.  (You don't want the nail
to
> > upset below the short reverse taper at the top of the header or you will
> > have an hourglass shape and it will stick.)
> >
> > The nail doesn't look like a cut nail -- i.e. a long straight taper -- 
but
> > rather a short taper to a point (about 3/8 of an inch) and then a long
> > rectangular section of about an inch and 1/4 followed by a 1/8 inch long
> > taper to the bottom of the head.  For the record Jerry used to make
nails
> > by
> > the 1000's for the reproduction hardware market.  The long rectangular
> > section is smaller than if it tapered its whole length -- hence less
> > volume.
> >
> > Dave Smucker
> >
> > ----- Original Message -----
> > From: "jj tobako" <jjtobako at juno.com>
> > To: <theforge at mailman.qth.net>
> > Sent: Saturday, July 03, 2004 4:15 PM
> > Subject: Re: [TheForge] nail header
> >
> >
> > >
> > > > As far as I know the historical nail makers always (or let us a
least
> > > > say
> > > > nearly always) formed a
> > > > shoulder, then cut almost through, inserted into the header, broke
> > > > off, and
> > > > then formed the head.
> > > >
> > > > Reason, -- more nails per length of wrought iron.
> > >
> > > how does that work?  why would a shoulder use less material than a
taper
> > > when heading?  the shank for each would be the same size (width at
> > > header, length of shank) unless the shouldered nail had a more
> > > rectangular shape which would be more iron, not less.  amount of iron
in
> > > the head is determined by where it's cut.
> > >
> > > john tobako
> > >
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