Hank Rearden
I wanted to share a technique I used to bend a 90 degree angle in a piece of 1/4"thick by 4" wide mild steel stock.

I used to chipping table to upset the angle. I didn't get a picture of that.

I folded it, then opened it then began to upset. The larger piece acted as a heat sink and dissipated the working heat quickly. It took many turns in the fire. Open to ideas or a better technique.

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code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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theengel
That looks very difficult.  You'd probably do better with a torch.  Even if you just used it after using the forge, to keep the heat on it.  Heck, even a butane might help.
Or, if not smithies per se, were you otherwise trained in the metallurgic arts before straitened circumstances forced you into a life of aimless wanderin'?
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Skarzs the Cave Troll
Don't think those little butane torches would be enough for that thick of steel.
Good job, Hank.
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theengel
I don't mean to heat it, I mean to keep it hot a little while longer as you're working it.
Or, if not smithies per se, were you otherwise trained in the metallurgic arts before straitened circumstances forced you into a life of aimless wanderin'?
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Hank Rearden
I don't think of Torch would generate heat in a large enough area and I would still have the issue of the heat dissipating because of the mass of the metal acting as a heat sink. I think the correct solution is to build a bigger fire.

My fire was hot enough it just wasn't big enough. I heated some coil spring after bending the plate and that only took a matter of moments to get to a orange yellow.

A bigger fire would generate heat over a larger area helping prevent it from cooling too quickly.
code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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Skarzs the Cave Troll
Yeah, that's the problem with those rivet forges: they don't have a wide or deep enough fire pot.
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Hank Rearden
When I got the forge I made some fire bricks with refactory cement. They make a more defined fire-pot. The bricks have worked excellent for keeping the heat away from the bottom of the pan. Also makes cleaning up easy. My thought was to make a ring of a steel about 2 inches high and the diameter of the forge. Then set it on top that way I can get a large pile of cosl over the tuyre and a larger ball of Fire. Has anybody else done anything like this?
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anvil
Hank, I'm going to suggest you get Francis Whitaker's book "the blacksmiths cookbook.

http://bluemoonpress.org/index.php/books/master-blacksmith/the-blacksmith-s-cookbook-recipes-in-iron.html

Without a doubt his technique for right angle bends is the quickest and most precise.

Otherwise I'll lay it out for you.

I consider right angle bends,,, to dimension,, a basic skill.
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Marc
From what I can see, it seems the steel was not hot enough. That size flat bar needs a lot of heat.
But you did well at the end and that is all it counts.  
The government cannot give to anybody anything that the government does not first take from somebody else.
Adrian Pierce Rogers
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Hank Rearden
Thanks Anvil for the book recommendation.

Marc, heat was an issue I want to put this in a hearth forge at eilliams Grove, to see if the heat allows better working metal.
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anvil
An observation or two,,

My riviting forge is my portable forge. I do not have any fire clay in it. No critique, just an observation.

However, you don't have enough coal in your forge. You need at least 4" of coke underneath and 2" on top. I can do this and maintain my fire in my riviting forge.

You need more hot iron. Shoot for at least a couple inches at a good yellow on each side of your bend. This gives you a residual heat source that "feeds" the area at the bend.

It may seem like a good way to do a right angle bend, but not so. First, it's twice the work. First you close it past a right angle, then you open it to a right angle,,, and have all that "stuff". [wink] To upset back into your angle. Just heat it as above, bend it either in your vice or over the edge of the anvil, and upset the right angle. Less stress, less coal, less time. I use my bending g fork/scrolling wrench combo of the right size for my bends. It's far more precise this way.

Altho I teach my students to forge a right angle completely by hammer and forge, the addition of ox/actl is perfect here. Use the forge for your initial heat and any time you lose most of your heat. Use gas with a "gas saver" to add a localized heat where needed when upsetting your angle.

For what it's worth, forging a right angle to dimension is easy if you know the formula for extra needed materisl to add to your angle.

Center punch for reference on the inside of the angle and add half the thickness of material to each side of the centerpunch. Take all measurements from the inside of the angle.

Do your upset on/over the edge of the anvil, not in a vice.

Hang the leg over the edge and upset using your hand to back up your blows. Leg down. Hold your angle far enough out to prevent forging the angle against your anvil

Next, place the bottom of the leg on your anvil face and upset using the anvil face as your backup.

When you hang it over the edge, upset with 4 blows,,, then when the anvil is your backup, use 3 blows.

There's one more step,,, lay both legs and the angle on the face of your anvil and with your crosspeen, move the extra upset material to the outer edge. This may be hard to visualize, but pics in his book show this.

Also, remember,, when you can forge a right angle to dimension, you can forge any angle bend to dimension.

Here's an example. These are elongated diamonds. Parent stock is 3/8"x1-1/2".
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Scrambler82
Hank,

An interesting method, from a Novices point of view, thanks.

Always had a problem keeping heat in a piece using a torch, that was my only way of bending steel back a few years, maybe more than a few.

At first I thought your piece was a thin piece of steel then noticed in the pictures that the steel was on the thicker side.

I will keep this method in mind for my next bending job, actually never thought of using the forge for just bending a piece of metal and now I have learned something new !

Thks / Ltr
Do It Right The First Time !
GrevB
Location: SoCal, USA
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anvil
Here's a pic of a bracket I made. The angles match the intersection of the log, then radiused to fit. Both legs are fitted to the log contour and radiused to match the log.

The purpose was to fit the bracket to the log, not blaze the log flat and just do a right angle bracket.
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Scrambler82
Those look great.

Do It Right The First Time !
GrevB
Location: SoCal, USA
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Hank Rearden
anvil wrote:
An observation or two,, My riviting forge is my portable forge. I do not have any fire clay in it. No critique, just an observation. However, you don't have enough coal in your forge. You need at least 4" of coke underneath and 2" on top. I can do this and maintain my fire in my riviting forge. You need more hot iron. Shoot for at least a couple inches at a good yellow on each side of your bend. This gives you a residual heat source that "feeds" the area at the bend. It may seem like a good way to do a right angle bend, but not so. First, it's twice the work. First you close it past a right angle, then you open it to a right angle,,, and have all that "stuff". [wink] To upset back into your angle. Just heat it as above, bend it either in your vice or over the edge of the anvil, and upset the right angle. Less stress, less coal, less time. I use my bending g fork/scrolling wrench combo of the right size for my bends. It's far more precise this way. Altho I teach my students to forge a right angle completely by hammer and forge, the addition of ox/actl is perfect here. Use the forge for your initial heat and any time you lose most of your heat. Use gas with a "gas saver" to add a localized heat where needed when upsetting your angle. For what it's worth, forging a right angle to dimension is easy if you know the formula for extra needed materisl to add to your angle. Center punch for reference on the inside of the angle and add half the thickness of material to each side of the centerpunch. Take all measurements from the inside of the angle. Do your upset on/over the edge of the anvil, not in a vice. Hang the leg over the edge and upset using your hand to back up your blows. Leg down. Hold your angle far enough out to prevent forging the angle against your anvil Next, place the bottom of the leg on your anvil face and upset using the anvil face as your backup. When you hang it over the edge, upset with 4 blows,,, then when the anvil is your backup, use 3 blows. There's one more step,,, lay both legs and the angle on the face of your anvil and with your crosspeen, move the extra upset material to the outer edge. This may be hard to visualize, but pics in his book show this. Also, remember,, when you can forge a right angle to dimension, you can forge any angle bend to dimension. Here's an example. These are elongated diamonds. Parent stock is 3/8"x1-1/2".


I agree with your observation on the amount of coal. I made thick bricks to help preserve the iron forge. I hope to roll a ring to set on the clay bricks to increase the depth of the fire pot.

I do appreciate the advice on the technique. I plan on try a few different ways of bending 90's. I bent a 90 in 1 inch square.  I need to do it two more times for a set of legs. I'll post if I do it consistently.
code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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anvil
Fun!

Another tip that may sound contrary to common sense.

Use a lighter hammer to do your upsetting. A heavy hammer will tend to mushroom where you strike instead of back where you want it.

A lighter hammer will transfer the force to the center of your "even" heat or where hottest with less distortion at the point of contact. Give it a try.
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