[TheForge] LG dies, was cast iron - Little Giant pulley

Tue Aug 13 14:06:00 2002

Ralph, this is something that I found in the scrap yard years ago.
They had several 4" x 4" x 20' long pieces of this 4340 that had been
lying around for years. One day Japh Howard & I stopped by to browse.
I showed him the stuff just because I was impressed with the size. He found
and translated the mil specs that were stenciled on this 4 x 4 stock in
yellow
paint about every 5 feet. he told me to buy a piece of it which I did and
got
for scrap price of the day ( 1987 ?) I still have about 4 or 5 feet of it
left
for making the dies for my big hammer. As I recall, Japh told me that this
stuff was annealed. I know that I can cut it with the band saw but can't
cut it within an inch of where the scrap yard had cut it in half with a big
oxy/propane  torch. I will try to find the specs. I know that I wrote them
down somewhere around here in 1987.................
dave m

>         Hi Dave,  I have used 4140 drops from a machine shop on my air
> hammer also.  The thing I just found out about this is it was 4140
> HT...........not 4140 annealed.  There are about five different grades of
> 4140 and 4340 when they come from the tool steel place(I've found out with
> some calling to Burgon tool steel).
>         I was wondering why the hell I had used this 4140 in my air hammer
> for three years and it had never dented with low profile tooling on the
top
> die.  Well I started making dies a few weeks ago with milled dovetails and
> found out about the different milling qualities of the tool steels as
> supplied in their different states/forms.
>         The 4140 HT does cut with carbide cutters.  The 4140 annealed cuts
> five times easier.  I found this out by being able to square up blocks
with
> .005 passes with a face mill.  On the 4140 that I got from Bob Bergman in
> Wisconsin it was annealed and I could take .025 in one pass with the face
> mill.    The 4140HT comes thru somewhat hard......about 40-45 rockwell.
> This does still cut with a carbide face mill, but passes were cut down 5
> fold as compared to the annealed.
>         Long story short is obviously I had welded on some 4140 HT to the
> air hammer for dies and this is why it held up so well for three years.  I
> tried some of the annealed material Bob gave me for a power hammer tool,
and
> it dulled very quickly.
>         Often we get material that is marked on the alloy, but the finer
> details are not given.  I found that all these 15 blocks of 4140 were
indeed
> 4140, but it was the HT not annealed as I could tell instantly by taking a
> .025 cut with a carbide mill head and if it chattered......it was HT, and
it
> it was annealed, it was fine to cut at that rate.
>         Just maybe the 4340 was an HT condition and not annealed as the
4340
> from what I'm told will take a real hardness of 55-60 rockwell if oil
> hardened.   The 4140 is only about 45-50, but the beauty of both alloys is
> the "toughness" of them.  They are both abrasion resistent, and impact
> steels for die alloys.
>         Just my findings from "found" 4140 at the scrap yard from cleaned
> out machine shops.  Interesting as to what a cutter pass can tell you.  I
> dug thru all the scraps and finally found one that had the HT designation
on
> one of the pieces.......this I further took to mean as this is what they
> bought to do the jobs they had for the materials.  Knowing what you have
can
> save time, money, and headaches.
>         If you just weld on the dies to a fastening plate........you'll
> never know if you had HT or annealed.  Both will weld and work......the HT
> will hold up for years, the annealed will dent from tooling impact.
>         Did you buy the 4340? or was it scrap from a machine shop? or tool
> and die maker?
>         One word of caution is when machining these alloys, some have lead
> in them, wear a respirator when milling unknown alloys.
>         I have built three of the air hammers so far, and had two of four
> die bolts come loose, but re-tightened and never a problem again.  I was
> cold texturing and the extra shock must have loosened them.  Hitting hot
> stock has never loosened the die mounting bolts.
>
>
> Ralph
>
>
>
> ----- Original Message -----
> From: "lama" <[email protected]>
> To: <[email protected]>
> Sent: Monday, August 12, 2002 12:22 AM
> Subject: Re: [TheForge] LG dies, was cast iron - Little Giant pulley
>
>
> > Ralph, the dies on my 75# Kinyon air hammer, my former 50# LG,
> > and my heavy treadle hammer are all made of 4340 not heat treated
> > in any way and in daily use for years & years and are still in great
> > condition. I am using 4"x4"x10-1/2" 4340 for the dies on my big air
> > hammer. By the way, my bolt-on dies have never come loose of their
> > own accord.
> > dave m
> >
> > ----- Original Message -----
> > From: "Ralph Sproul" <[email protected]>
> > To: <[email protected]>
> > Sent: Sunday, August 11, 2002 8:05 PM
> > Subject: Re: [TheForge] LG dies, was cast iron - Little Giant pulley
> >
> >
> > >         Cameron, I find no reason at all not to use 4140 for hammer
> dies.
> > >         You may find many a damaged cutter if you try to mill a forged
> > piece
> > > of 4140.  It is a chrome alloy and will get hard in the air to a
certain
> > > degree.   Welding to 4140 will yield hard spots that will dull
inserts,
> > and
> > > take the rake of your band saw blades.  I think it is wishful thinking
> to
> > > figure your going to make an accurate set of dovetails on a press.
> > >     If you have a milling machine, buy the stock the right size, and
> mill
> > it
> > > the first time.....your short cut will cost you in the long run.
> > >         My two cents.
> > >
> > > Ralph Sproul - Bear Hill Blacksmith
> > > Webster, NH
> > >
> > >
> > >
> > >
> > >
> >
> >
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