[TheForge] scrap plate steel

[Ralph Sproul]

Pete,
I've used this heat & quench technique to straighten welded lumber fences in
sawmills made of tubing or heavy flat.  It works extremely well, but my
guess is it would use more heat/gas to do plate than just paying for the new
steel and building your table.

I've had better results rolling over 1/2-3/4 plate with a loaded gravel or
log truck with first strapping, then rough sawn boards, then 2 x 4's as
riser blocks.  This works much faster than a torch on slightly warped plate
(which I would consider a 3/8 offset).

I also use this technique to curve 3/8 plate bases to make post vice stands
out of.

My boom truck weighs 28,000 lbs empty and full of rock on the deck it is in
the 50,000-60,000 lb range.

It's crude, but effective.

Getting a 1/2" bent plate totally straight is going to be difficult, but
another thing I've used is 4" channel stringers between the legs to clamp
down the plate to make it as straight as possible for layout.  STITCH weld!
do not full weld........or you'll pull the table into another curve.  I got
8-12 inches apart on the stitches.......on opposite sides of the channel.

Ralph

----- Original Message -----
From: "Peter Fels And Phoebe Palmer" <artgawk at thegrid.net>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Saturday, October 16, 2004 1:26 AM
Subject: Re: [TheForge] scrap plate steel


> I think the theory here is that one heats a limited area to dull red and
> the surrounding plate prevents it from expanding, so it upsets then
> shrinks flatter  on cooling .
>
> The Millers wrote:
>
> > Actually it is kind of counter intuitive. You heat the convex side
> > then "chill" it with water causing rapid contraction.
> > The rapid contraction performs the "shrinking" effect like a shrinking
> > hammer.
> >
> > You can't do it all at once.
> >
> > But I watched a guy straighten a 24" buck stay, (I beam used in large
> > power plant boilers) that had a 12 " bend!!
> >
> > Ray
> >
> >
> > The other model to consider is heating couplings to install on shafts
> > or shrink fits.
> >
> > If you heat from the outside in the hole will get smaller. If you heat
> > from the inside out it will get bigger.
> >
> > Ray
> > Cincinnati
> >
> >
> > On Friday, October 15, 2004, at 05:02 PM, Gladish Family wrote:
> >
> >>> In basic terms it was a matter of heating the opposite side and
> >>> then cooling with water and shrinking the "dimple".
> >>>
> >>> Ray
> >>> Cincinnati
> >>
> >> That sounds kind of fun...so, the heat goes in the concave side, right?
> >> Then (I'm guessing here) heat until it expands and becomes straight,
and
> >> stop it in time...
> >> Andy G.
> >>
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