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I Forge Iron

The forge lives! Now I need some advice...


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So I got the new forge fired up properly this evening. I used charcoal to get it going then piled the coke on top and this thing is AWESOME!





Like I said, I knew nothing about blacksmithing three weeks ago and have never actually seen a proper forge working so to me this was something really incredible - I've never seen anything quite like it! I can't emphasize enough how happy I am with this forge. It got so hot I accidentally melted my 50x50x5 angle iron. The firepot was glowing red and I was concerned about it melting but when I cleared the fire at the end it had held up beautifully. After my last post, many people expressed concerns about the air holes in the bottom of my fire pot, but I can tell you they did not present any issue at all. The blower performed admirably and I only ever needed to open the air gate a fraction, just a few mill was enough! If I opened it fully it really roared and I knew if would eat through my fuel in short measure.

Anyway, as I mentioned before,the reason I built this forge is so I could put a 45 degree bend in angle iron, otherwise known as a "knee". I also need to "joggle" angle iron like the old angle iron smiths used to when making riveted plate girders.

I was able to successfully heat the angle iron in the pot with no problem:


And here are the results:






I suppose I was able to have some success here. The result I'm looking for is a clean 45 degree bend in one axis, as in the last photo. I began the bend by hooking it in one of the t-slots on my surface table. Inevitably, the steel on the "hard bend" leg puckered up so I hammered it as I bent. Eventually I was able to draw this out so that it formed a curve in the inside edge. I was then able to sharpen the outside corner somewhat, but ideally want to get this cleaner than it is. As you can see, I left it soaking too long and melted the inside radius of the angle iron. I was surprised how quickly this can happen. I suppose the correct timing will come with experience.

So basically, my question to any of you is - how can I best achieve what I want to? Currently I have no anvil as such, I used the edges of my t-slot surface table as an anvil and it did not damage it at all. I do however have a 30 ton pneumatic workshop press, which could easily perform a bending operation in one heat.

So - can anyone suggest a technique I should use to do this? I could make up some press tooling from steel plate and use that to bend it, but I would still get some puckering on the "hard side".

Alternatively, I'm thinking about a technique involving bending it over a slotted die by hand then hammering down the pucker. On the next heat I could draw out the excess from the pucker to form a curve on the inside edge, then refine the outside corner with a few hammer blows on the last heat. Does this sound like a reasonable approach? Should I upset the steel at the point of the bend before bending it? Also I thought it may be worth quenching the heat on both sides of the bend point to isolate the work to a smaller area.

Apologies for the barrage of questions but I hope someone can advise me. I realise I should probably go on a course but I really don't have time for that as I have already left my "proper job" to do this. This operation is just a small but essential step in my production process so I need to get it right quickly. I am a very fast learner (not only was the forge my first forge, but also my first welded fabrication - I had only done practice welds beforehand), so any advice you can offer would be quickly applied.

I know there are some experienced blacksmiths on here so hopefully someone can give me some solid advice or otherwise direct me to useful sources.

Thanks in advance...

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Thanks Charles, I shall be attempting that technique next time. There's really nobody left to teach this stuff any more and most of the reference material was written by engineers who never got their hands dirty. No doubt the actual doing of the job was learnt through apprenticeships...

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Acualy the information you are looking for are old blacksmithing manuals that either are pre copyright or that have expired. Not many coledge trained "enginears" in 1890, lol. 

Weygers' complete modern blacksmith has a page dedicated to bending and forging a 90degree corner on angel, just dont bend it so far. Either lea e the curved inside corner or forge it in and clean up with a file (another heat usualy hides the file marks well)

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This fire was a little large to be honest, I could do with it a little smaller so I can get a more local heat on the area I want to bend. I guess I just wanted to see what she was capable of this time.

I suppose I could get some fire bricks and cut them so they take up some room at either end of the pot. I also found I had to build up the fire quite high in order to get the angle iron sitting nicely in the sweet spot. Perhaps another grill  in the bottom would help more to raise the fire above the rim of the pot with less need for excess fuel. Any other suggestions?

I do have an air gate on the forge and closed it off after each soak. Eventually I realised it was best to open up the fire each time to release some heat and reduce consumption.

I'm not overly concerned about consumption though, the main thing is it will provide what I need when I need it. I won't be forging continuously for 8 hours a day, five days a week. It'll be more like three hours every three weeks. Once I get the technique down I'll just blast out a load of bent angle sections in one session and use them as required. Although it's bespoke furniture I'm making, many of the elements will be the same across the board.

Edited by Thanaton23
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Just a quick update on this. I made a joggling die for the hydraulic press. It's not pretty but it works great:






It's not exactly how I want it but it will certainly allow riveted construction with angle iron. I have a few ideas to perfect the technique.

I also made this as my first completed forged project, a rivet set made from some 1" round I had. I formed the end over a 3/8" rivet held in a vice. I then attempted to harden and temper it with another soak in the fire, quenched the end then allowed the tempering colours to work their way up to the tip. It was going slow at first but sped up towards the end (I guess it does this because there's less material to draw the heat as it gets closer to the tip) and I wasn't quick enough to quench it so it's tempered to around blue/purple. I guess this should be OK for an impact tool like this but It's also too shallow so I'll be doing another one with a deeper cupping...


Also, the forge is performing superbly. I was able to get a nice steady fire going tonight and used a LOT less fuel than the first time. If I shut the gate between heats it just ticks over nicely. I can go off and do other things and it will look after itself. So far, it has vastly exceeded my expectations...

Edited by Thanaton23
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Tempering colours are useless without knowing the alloy---1030 you may want straw where 1095 blue may be best for a certain project.  Shoot some alloys won't harden when quenched and so tempering colors are rather a waste of time on those.  For unknown alloys junkyard steel rules apply---meaning you test the hardening and tempering variations until you get something that works or you abandon it for a different piece of metal.

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This is just mild steel round bar from a local steel merchant. I have no idea what alloy it is but I have several meters so I can afford to experiment. TBH, it didn't seem much harder as I removed material fairly easily with the angle grinder and a sanding disc. What alloy of steel would be best suited for this application?

Edited by Thanaton23
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