Forging advice

[Carlos Lara]

The last time I tried my hand at forging wrought iron, it was to try to flatten a ~1.5 by 1.5 x~3 inch billet. The billet started about 1.5x1.5x6 inches, but one end never really heated up well, and so I cut it in half to try to save time. However, there reached a point where the billet was forming into a bowl shape. To try to flatten it, I would turn it around after each forging, but I would end up with the same shape again, and it wouldn't be any flatter. 

 

Now, for shibuichi, I know there's a maximum depth you can forge it, and once you get to this, you have to anneal the metal again to get it any thinner. Is wrought iron like that? It may also be the billet is a bit thick, and it's hard for the white heat to get all the way through it. I'm going to try some ship chain next time, so it should be a bit easier to get it into a 4mm thick plate, but I figured I would ask since I am a newbie!

[Alan Longmire]

Wrought has to be forged at as close to welding heat as possible.  Lower grades will crumble or split if worked down below a bright orange heat.  Just keep it screaming hot and keep going.

 

I'm having trouble picturing it forming a bowl that won't flatten. Are you trying to upset it longways?  The grain in tsuba should run vertically, not end-on.  If you're trying to turn 1.5" square bar into 4mm plate, just cut a chunk about half as long as your tsuba is tall and work it with a cross peen to try and force the 1.5 inch dimension wider.  It'll spread in all dimensions, but you should easily get a 4" x 4" rounded square of 4mm plate out of a 1.5 x 1.5x 2" bar, if not two, depending on losses to scale.

 

That said, 1.5" square is a crazy big bar to try and hand forge.  Let that sucker soak for a long time to be sure it's hot enough.

[Carlos Lara]

Thanks Alan. Here's a picture:

 

 

 

 

I'm sure part of it is my technique, but I also think you're right it just isn't hot enough. I tried my best to start in the middle and work my way out, but the edges were clearly moving more than the centre. I don't have a cross peen though, I've been doing everything with my Japanese forging hammer, so maybe that has something to do with it. I've seen videos on how to work with the cross peen, so maybe that's my next purchase! As far as I understand, the wrought's strands should go in the plane of the tsuba, so that at the rim they are visible as lines. In the piece above, the lines are horizontal when looked at from the small side. You'll see the top has a curve, I was trying to hammer that out by flipping it upside down, but it ended up looking the same on the other side! I think if I heat it up more though, it will take the thinning out better. 

[Dan Hertzson]

As Alan mentioned, working that size piece without either a power hammer or press is going to be a struggle.  Wrought, properly heated to screaming yellow heat, actually works down easier than even mild steel, but you need a heavy hammer to project down through that kind of thickness.  Yes I know a lot of folks theorize that it is all about kinetic energy, and swing velocity is the primary variable (kinetic energy as a function of velocity squared).  My counter to that is just try to break down a 2" round of any type of steel with a 1 LB hammer and a 4 1/2 LB hammer.  I don't care how fast you swing the former, you just aren't going to get far, and the latter will make a significant impression.  My theory is that hammer momentum is actually what we should be considering, and for that hammer mass and velocity are equally important.

 

Bottom line is I recommend you heat it hot and soak it till it is heated through.  Then get a buddy to strike for you with at least an 8 LB sledge... Nothing wrong with a Japanese style, forward weighted, forging hammer.  You just need to use a large enough one.

 

If not, perhaps you can send it out to someone with a power hammer for initial processing.  If it is good, knarly wrought, you might find someone who can help you for a portion of the stock. 

[Dick Sexstone]

That is way more material than you need to get to 4 MM thick .....you could cut it in half again and still wind up with a bigger piece than you need..... and it doesn't sound like you were getting it hot all the way through .....so a smaller piece would help you get the whole billet up to bright yellow heat also......

[Carlos Lara]

Thanks! Yes, you're probably right. It probably does make sense to cut it again. New at this, so not sure yet how much I needed!

[billyO]

On 8/7/2023 at 1:50 PM, Carlos Lara said:

New at this...

On 8/1/2023 at 5:16 PM, Carlos Lara said:

but the edges were clearly moving more than the centre...

Noticing this while forging is clear evidence of the piece is too large for the force of blows (unless of course that was what you were going for).   Either swing harder or pick a smaller piece.

Dan gave a good explanation (and I agree with him that too many smiths focus on 1/2 m v squared).
During my classes, I always introduce my students to this concept of how (remembering that everything is relative to the size of the piece) heavier and lighter blows will move the steel on the first day at the chalk board by drawing something like this:

 

 

 

 

Edited August 11 by billyO

[Carlos Lara]

Thanks all! I picked up a few forging hammers from a local store, the heaviest 2 kilos! I'm going to half this piece again and try with that. I predict it's going to go better this time!

[Carlos Lara]

So I had a few hours at the forge today, and am happy to report it worked out perfectly! The 2 kilo hammer, particularly if I hit with it just right (from the hips like a Japanese sword), moves a lot more metal at a time than I was ever able to move before. I halved the billet, and so I got it down to 4mm in only about 2 hours. The funny thing is that I also tried my hand at some steel for the first time while I was waiting to heat up the iron, some pieces of W2 to turn into chasing chisels, and I was surprised at how fast they heat up and how easy they were to work. Once you've worked with wrought iron, everything else is easy! I'm glad I got (now) four hammers, a 500g, the 750g Japanese hammer, a 1 kg and a 2 kilo. There's times all of them seem to be useful.

 

Here's the tsuba blank in the middle. I still have to improve the surface, and I'm going to try to get it more round by forging in the corners, but I'm still very happy with how it turned out! I hit it with the 1 kg cross pean at the end to try to make it a bit wider, which seemed to work, but you can see I didn't fully hammer out the cross pean marks. I don't want it too flat though, so I'll hammer them out when I round the corners. I brought more pieces out than I had time to work on, but I'll get to them in due time! You can see there some of the ship chain Geoff got for me. 

 

Here's my current setup. I got some ceramic plates that Alan recommended, and they are working much better than before. The plan is to make them into doors eventually! My wife was complaining that I was burning the grass, so that's why I got this welding table! I think I need a bigger anvil, I'm really starting to feel it's a bit too small.

 

[billyO]

15 hours ago, Carlos Lara said:

Once you've worked with wrought iron, everything else is easy!

I'm not sure that the material was wrought iron was the issue, rather it was the size of the stock you were trying to forge. 

So I think what you mean is: "Once you've worked with 40mm thick stock, anything under 15mm is easy."

[Carlos Lara]

Haha, that's true!

[Charles dP]

On 8/17/2023 at 10:39 PM, Carlos Lara said:

I think I need a bigger anvil

It’s normal to feel that way, we all do .

 

Are you using the anvil on the lawn like that or was that just for the photoshoot?

[Carlos Lara]

Yes, I was using the anvil on the lawn, on that bit of sheet metal, but I need to get a better solution! I do a lot of work on my knees, so that's ok, but it's not very stable! I think I'll make some sort of wooden platform for it. I'll wait until I get the bigger anvil first though, and make the platform for it!

[Alan Longmire]

Even if you work sitting down, the anvil HAS to be anchored firmly to an immoveable object to be useful.  The Japanese use a buried stump.  That's one of those little 66lb/30Kg cast steel ones, isn't it?  If you bolt it down to a firm surface it'll feel to the hammer like it weighs four times as much.  You're losing all your hammer's energy to moving the anvil around otherwise. Every time the anvil moves, it's that much energy you're not putting into the hot metal.  The lightest anvil I'd even think about using without bolting down would be above 500 lb / 227 Kg.    

[Carlos Lara]

Ah, you're right, I didn't think of that. It's something like 30 kilos for sure. That's next on the to do list then, make a proper support for the anvil!

[Geoff Keyes]

If you're going to build block, be sure to orient it end grain up.  I tried to build a block out of 2x4 cutoffs laid on their sides and it was spongy.  If your setup needs to be mobile, you can't used a really big block, unless you can leave the block in place and just move the anvil.  And before you ask, no, you can't build a block out of concrete, though you can set a block on a slab of concrete.

 

You might find some useful ideas here.

 

Geoff

 

[billyO]

10 hours ago, Carlos Lara said:

Yes, I was using the anvil on the lawn, on that bit of sheet metal, but I need to get a better solution!

If you have access to steel and a welder, tripod anvil stands are nice and sturdy.

Edited August 21 by billyO

[Carlos Lara]

Thanks Geoff and Billy, good advice. That's a good post about anvils. I have a good amount of scrap wood I can cut and glue together grain up, so that will be a start! At the moment I have to forge outside, as in my garage it's probably not very safe. I also have a welder and a fair bit of scrap steel, so once I get the platform done I can look into making a stand for it! 

[Geoff Keyes]

Steel stands are nice for some things.  I have one I built to hold a 125# anvil that I take to demos and workshops.  It's portable, but it's a little bouncy for my taste and the little Hay Budden I built it for rings like a bell in that stand.  Portable blacksmith tools are kind of a non sequitur, kind of like a pocket cannon or a flying horse.  The best tools are fixed in place, like the 1000#+ tool stand that is my anvil, hammer rack, swage block and tool holder.  It does not move without some real need.  I can get a pinch bar under it and put it on rollers, if I have to.  The best thing for a small anvil would be a block buried in the ground, second best ( or perhaps third best ) is a portable block of some sort.  But you have to do what you have to do, and even a bad setup is better than nothing at all.

 

Geoff 

[billyO]

6 hours ago, Geoff Keyes said:

Portable blacksmith tools are kind of a non sequitur, kind of like a pocket cannon or a flying horse. 

18 hours ago, Alan Longmire said:

The lightest anvil I'd even think about using without bolting down would be above 500 lb / 227 Kg.    

Agreed.  One thing I didn't mention about my set-up in the picture.  The anvil is a 150KG Kohlswa, the base is a 12" square piece of 2" plate, and the legs are filled with sand and oil (for added weight and to reduce ringing), so the entire thing is about #450+

 

 

Edited August 21 by billyO

[Alan Longmire]

9 hours ago, Geoff Keyes said:

Portable blacksmith tools

 

The way I heard it phrased was "When a blacksmith says he has a portable hammer/press/etc., that means it can be moved, if you are very determined and hopefully have a forklift handy."  I've also heard "Portable" has a different meaning to a blacksmith than to an ordinary person, as to a smith it means the tool in question is not permanently built into the structure of the building.  Note this doesn't mean you may not have to tear out a wall or roof to move it!

 

My main anvil sits bolted to a pair of 10" x 12" bridge timbers, bolted together side by side.  If that were not in turn bolted to the floor I could roll it outside with a two-wheel dolly, but the whole assembly weighs around 400 pounds.  

 

My guild's "portable" anvil is a 144lb Peter Wright that sits on a ~30" oak round that weighs around 110 pounds on its own.  It works fine, but it still jumps if you're really wailing on it.  

 

One old smithing guide I have says your main anvil should be at least 150 pounds, and that it should be strapped down to a 24" diameter Elm log eight feet long, six feet of which are buried in the shop floor, as only that would provide a stable enough mount for such an important tool.

 

You get the idea.  A solidly mounted anvil is your friend!

[Carlos Lara]

Here's what I came up with:

 

 

I buy these 2x8 foot boards from a big box store for a variety of projects. The wood is "white wood," and comes kerfed end to end and glued side to side to make the board. It's not the best wood ever cut, but the price is right, and it's handy for a lot of furniture style projects. I cut a bunch of scrap of these boards 6 inches perpendicular to the grain, and glued them all together with wood glue. It didn't glue perfectly square (I should have used more clamps!), so I cut out where the anvil was going to sit with a chisel. It works great though! It probably weighs at least 30 kilos itself, and the little anvil I have feels much more stable on it. The steel bar behind it I'm planning to cut into a frame to help keep the anvil in place. Doesn't look pretty, but it works!