[TheForge] Upsetting the middle of a bar

[Jerry Frost]

The hydraulic powered upsetter was Terry R.'s contribution.

While similar my contribution was operated with a putting stroke by a sledge
hammer.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.


----- Original Message -----
From: "Peter Fels And Phoebe Palmer" <artgawk at thegrid.net>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Thursday, October 28, 2004 8:05 PM
Subject: Re: [TheForge] Upsetting the middle of a bar


> Hello Bruce and Stephen;
> This technique is called "jumping" and  is worth setting up if you have
> a bunch of them to do.
> Frosty's hydraulic jack proposal sounds good too.
> In the past I've just used a piece of pipe a bit shorter than the bar
> and a heavy baseplate with a welded ring that the pipe fits into. The
> pipe is a little bigger ID than the upset.
>  Spot heat the area to be upset and drop it down the pipe to the
> baseplate and honk on it with a sledge. You'll probably have to drive
> the bar out with a drift and take another heat to straighten it out. Way
> quicker than the multiple heats otherwise necessary.
> Pete F
>
> Bruce Freeman wrote:
>
> >The following is either "book larnin'" or else something I picked up
> >from a demonstration or a video - I just don't remember.  But I haven't
> >tried it myself.
> >
> >First, the physics:  If you tie a steel cable tightly between a heavy,
> >movable object and an immovable object, then push sideways on the middle
> >of the cable, the heavy object can be moved with ease.  The reason is
> >that the relatively small force exerted sideways on the cable is
> >translated into a large tension on the cable that can move the heavy
> >object.  It's rather like leverage, but different.  If you've never
> >played with this, try it with small objects and you'll be convinced...
> >
> >This upsetting technique is sort of the inverse of the above technique
> >- a sideways force is put on a slightly bent bar to exert high
> >compression force along the length of the bar.  Drop a couple of drift
> >pins in your acorn table, separated by a little more than the length of
> >the ballaster bar.  Against one of the pins, put a (sideways) "stack" of
> >"shims" to reduce the distance between the pins to something a little
> >less than the length of the ballaster bar.
> >
> >Heat the ballaster bar to yellow in the center (preferably with a
> >torch, but heating on a forge and selectively cooling should work too).
> >Bend the bar slightly at the hot spot, place it between the two
> >pins/shims with the bend up, and press (or hammer) the bar down.  Repeat
> >this step, adding shims, until the desired upset is obtained.
> >
> >Bruce
> >NJ
> >
> >
> >
> >>>>irony at epowerc.net 10/27/2004 10:40:29 PM >>>
> >>>>
> >>>>
> >Y'all:
> >I have a stair and a parapet railing to make with about 60 balusters,
> >each having a long leaf forge welded near the middle of each bar.  My
> >stock is 5/8 square.  I am looking for a simple way to upset each bar
> >for the weld and am not having much luck.  I have used my coal forge
> >with a fairly narrow fire on some and on others, a rosebud to make the
> >heated area shorter.  I have been using a 2-1/2" depression in a swage
> >block as a base and either a 4# hand hammer or a special tool for my
> >air
> >chisel that is a cup about 3" deep.  Either way the process seems far
> >too slow.  If I use the air chisel and keep the rosebud on the stock
> >constantly at almost a welding heat it barely upsets the metal even
> >after 5 heat/upset/straighten distortion cycles.  Using the hand
> >hammer
> >seems to be the fastest way, but even that way it still takes 5 heats
> >or
> >so.  Is there something basic I'm not seeing here?
> >
> > Stephen McGehee
> > Publisher of
> > Irony, the sketchbook of an apprentice blacksmith
> > P. O. Box 9822  Pine Bluff, AR 71611
> > irony at epowerc.net
> > (870) 540-0142
> > (479) 643-3299 (farm)
> > You can see a sample of IRONY magazine here:
> >
> >  http://lametalsmiths.org/news/page4.htm  )
> >
> >
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