I am usually working with round or square less than 1" x 30".
All I end up doing is bending the piece where I am attempting to offset it.
I beat the piece on its end, on top of the anvil. I even made a jig so I
could beat it sideways into the anvil. No help. It just bends. I use a
propane forge and I have not tried cooling most of the stock before
hammering. I don't like the idea of putting my single anvil on the ground
and using long stock and a stepladder.
Sure could use some suggestions. I went back to my teacher last week and
forgot to ask him how to do it. He's out of state for 3 weeks now.
charlie in MT.
What is offsetting? I'm new the blacksmithing. Are you just trying to
form a jag in the piece such as two 90 deg turns close together so that the
long ends still remain parallel?
Here's a reference on the web I found that should give you some ideas if
that's what you are trying to do:
Your talk of a the anvil on the ground and a stepladder however doesn't
seem to make any sense.
Are you actually asking how you can _upset_ the material (make it thicker
by hammering on the end)?
If that's what you are trying to do there are are few things I could
suggest (though I'm certainly no expert here).
First, yes, it will always try to bend on your. You can't heat up a
large section of the rod and try to upset it. It will just bend. You have
to work on small sections at a time. As you said, if your gas forge is
heating up too much metal, cool down the stock except in the small section
you want to work on. you just have to keep repeating like that for the
entire area you want to upset. Even then it will bend on you, and you
simply have to stop and straighten it out from time to time (which also
undoes some of your upsetting work).
Upsetting is a slow and hard work. Don't expect it to go fast - it takes
time. However, the hotter you can get the metal, the better - as far as
speed. Push it all the way just short of burning if you are trying to do a
lot of upsetting.
The little upsetting work I've done, was achieved by laying the bar flat
across the anvil, holding it tight with my left hand against my leg to
create a little more mass to hit against - and then just lending over the
anvil and hitting the far end back towards me. The longer and heaver the
piece, the better that technique works because the mass of the piece itself
creates the back force to do the work for you.
If the piece is short enough, you can stand it up on end on the anvil and
hit down with the hot end up. If your anvil has an upsetting block (a
block that comes out the bottom typical on the back side) you can use that
to deal with longer pieces. You can also put the hot end down, though it
will cool faster if the end is hot and in contact with the anvil.
For longer heaver pieces, you can use the mass of the work to act as the
hammer. That is, instead of using a hammer, just hold the work with the
hot end down and bang it down against the anvil letting the mass of the
piece do the work for you.
I've never tried it (or seen it done) but for long pieces I guess you could
try to use the side of the anvil and hammer against that. But you don't
even need to use the anvil. For a long piece (many feet) the piece itself
has enough mass that you can just hit the hot end and let the mass of the
piece act as it's own anvil. Anything you can rest the piece against could
be used. If you have a hard concrete floor I would think simply placing a
think plate on the floor and then using that to hit down one would work
nicely (but don't blame me if you develop cracks in your floor!).
Watch out for the hot end mushrooming out into a sharp edge. Don't let
that happen. If it goes too far, you won't be able to hammer it back
without folding it over. You have to keep hammering it back, and you can
even bevel the end so that mushroom effect causes it to return back to a
straight (but wider) side.
That's about the limit of what I currently know about upsetting (if that
was what you were asking about).
It sounds like you mean "upsetting", as the second operation you are
describing sounds like "jumping".
There are a couple of ways to do this.
One is the first method you described, by laying the piece over the edge
of the anvil and hitting it horizontally. I suspect that you are trying
to do too much, try heating a smaller area and don't over hang the anvil
The second method is jumping, and this will work to a degree. You're
only heating the end, the middle should be fairly cool to a pair of
gloved hands. Get a really thick steel plate and put it on the floor
and jump the hot end onto that.
The third method, was told to me by someone on one of these groups, but
due to the nature of my news reader, I can't give him proper credit,
although I do appreciate it. This does work. Put a small bend on the
piece of your steel, then place the bend on your anvil with the end of
the steel pointing up. Beat that. This will give you a reasonable
upset that you just need to tidy up a little.
I think you have gotten some good advice already, so I'll just add a
thing or two:
Always upset at a "welding heat". Stop hitting the work when it gets
below orange and re heat it.
Plan for cooling the work behind the area to be upset, so when you DO
pour water over that area you can do it quickly. You don't have to cool
the area so far that the color is gone. Just enough so its cooler than
the end. Can you change the location of the work in the forge so only
the end is getting really hot? Is there a hot spot in the forge that
you can use to get the work even hotter?
Try this: Heat the work as hot as it can get. Pull it out of the
forge and quench the area in back of the end to be upset. Put the part
back in the forge and reheat. This will give the end to be upset a
"head start" on the rest of the bar.
If you are holding the work with one hand, plan to rotate it often as
you hit it. This will minimize bending. But, bending will almost
always occur, so be prepared to correct it at once, before it gets out
I have found that clamping the part sideways in the leg vise works very
well for upsetting. The part is held more or less in one place so you
can concentrate on watching the progress of the upset as you hit it.
You can slightly adjust the hammer blows to minimize bending because you
can see what's happening easier.
You have probably gotten the idea by now that you need a high heat to
upset. If you can't forge weld with your gas forge (get the work almost
white hot), then maybe the forge needs some adjustment.
You may not notice any appreciable upset occurring for the first couple
of heats, but keep at it (more heats) and the upset will begin to show.
You may only get 3 or 4 wacks at the part with each heat, before it's
time to reheat. The reason I tell you this is that I remember when I
first started blacksmithing---- I wanted to get every ounce of work I
could out of every heat, so I ended up beating on a lot of cold iron.
That, of course, is one of the two major blacksmithing no-no's. But,
it's even a worse idea when upsetting.
By the way, I think Francis Whittacker told people later in his life
that he had ruined his non-hammer wrist by holding the iron while
upsetting sideways on the anvil. Someone can correct me if I'm wrong
Just a small point, you can forge weld with a gas forge that doesn't get
the metal really hot. It's harder to do, but it can be done (definitely
after a lot of tears :-( )
I have the pieces for my micro forge ready to go, just need to put the
A 2" firebox, powered by a JTH-7, should be sufficient to make my forge
welding life a lot easier.
I don't doubt that, but there are so many gas forges out there that
don't get very hot and/or are run in a very oxidizing mode that I feel
its important to mention the importance of "hot enough".
One person I met had built a gas forge from plans, in a workshop with
others, but simply decided to use only the about 1/4 the gas pressure
to save money (a 15 psi regulator when 60 psi was called for). And then
they wondered why it didn't heat things very well. When this sort of
thing happens, the owners do things to try to make it better, such as
adding a LOT more air to get the temp up. This means the forge is
running 'way too lean. On the forge I mentioned, above, it reduced a
1" square bar to a 3/4" square bar in 15 minutes.
Of course, and a lot of the forge designs are not really designed with a
great capacity of heat in mind. Jim had Don Fogg over making a gas
forge for him, apparently it's blisteringly hot.
I've learnt a lot from the deficiencies of my previous forges, and if
the micro forge I'm making works out, the whisper momma will be used a
lot less ;-)
Basically if your gas forge isn't hot enough, there are a few things
that you can do to make it work better.
1) Reduce the firebox size, it doesn't have to be by much. Using an
example of the whisper momma, I wasn't able to forge weld in it at all,
until I lined the bottom with 3/4" hard fire brick. Forge welds a lot
better, still not as easy as using coal, but not too shabby.
2) Increase the PSI, more gas means more heat... usually.
Eventually you make something that works.
I use a gas forge for convenience, and getting solid fuel other than
charcoal in Australia is getting very difficult.
The other forge that I think that is a really good idea is an induction
forge. Clean and quick.
Regards Charles from Oz
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