Hammering on laminated billet's edge

[musicman980]

Is there a certain temperature range or maybe a technique one should use when hammering the side of a laminated billet to prevent delamination? The goal is to make a takefu shiro 2 suminagashi billet just a little thicker.

Also, just out of curiosity, would all three layers expand at the same ratio, or is it common for some steels to compress and others to squeeze out somewhere else?

Thanks, I'm a newbie!

 

[Stacy E. Apelt - Bladesmith]

It should be done at near welding heat ... 2100-2150F.
However, it is doubtful that the layers will evenly expand or stay straight.

It would be far better to either purchase a thicker billet, use this one and have a thinner blade, of have someone make a billet to your requirements.

 

[musicman980]

Thanks for the prompt reply, Stacy. Darn... I only need it to be 1-2mm thicker (5.5 going to 7-7.5mm)

What typically happens when you hammer a laminated billet on its side at say 1400 and below? Would normalizing the grain first help any with the even expansion?

 

[HSC ///]

The goal is to make a takefu shiro 2 suminagashi billet just a little thicker.

Isn't this the 22 layer bar? If so, I use this alot. You can certainly end forge it, although I've never made or needed to make it thicker as you are asking.
End forging at lower heat you risk cracking, although I've never seen it happen with this steel.

I think the devil is in the details as far as what you are asking....are you wanting to make just a portion of the bar thicker as in for the ricasso? or thicken the entire bar? and over what length?

 

[musicman980]

Yes, that 22+1 layer 5.5mm thick bar. It seems like a great price for what it is and I figured I'd try to squeeze out some extra width. I would love to hear your opinion on it's forge weld quality.

I would be making some Japanese style chisels. 2.25" length heads for the bench chisels, and longer for the paring chisels. The heads would be tapered, thicker in the back. Without any thickening by forging, since the billets have 2mm of soft steel on either side, that means that the front of the head would be ground to 3.5mm thick to expose the white steel on the bottom, and the back of the head would remain 5.5mm thick. That's fine for some usu-nomi paring chisels I guess, but I don't think would be beefy enough for bench chisels. What would be awesome is if I can get 5mm up front, and 7.5mm in the back for bench chisels, but I'm ok with a little thinner if that's too much expansion.

The neck and tang would indeed have to be brought in even more to a round or square cross section, but I wouldn't be caring about the evenness of the expansion of the layers in those areas, as long as they don't crack.

I do hope my idea isn't too confusing or out of reach, I'm still in the planning phase.

 

[HSC ///]

Yes, that 22+1 layer 5.5mm thick bar. It seems like a great price for what it is and I figured I'd try to squeeze out some extra width. I would love to hear your opinion on it's forge weld quality.

I would be making some Japanese style chisels. 2.25" length heads for the bench chisels, and longer for the paring chisels. The heads would be tapered, thicker in the back. Without any thickening by forging, since the billets have 2mm of soft steel on either side, that means that the front of the head would be ground to 3.5mm thick to expose the white steel on the bottom, and the back of the head would remain 5.5mm thick. That's fine for some usu-nomi paring chisels I guess, but I don't think would be beefy enough for bench chisels. What would be awesome is if I can get 5mm up front, and 7.5mm in the back for bench chisels, but I'm ok with a little thinner if that's too much expansion.

The neck and tang would indeed have to be brought in even more to a round or square cross section, but I wouldn't be caring about the evenness of the expansion of the layers in those areas, as long as they don't crack.

I do hope my idea isn't too confusing or out of reach, I'm still in the planning phase.

I don’t have any opinion or knowledge on the forge weld quality. I have never operated at that temperature on the steel
Personally I think that temperature is too hot for the steel but I’m not an expert so I’m not going to question what Stacy just suggested

My advice to you is the cut off 2 inches and heat treat it and grind it and do some testing and I think you’ll have the answers that you need for your application

 

[musicman980]

My advice to you is the cut off 2 inches and heat treat it and grind it and do some testing and I think you’ll have the answers that you need for your application

Sounds good. If I may, would the cracking issue likely occur during the forging, or during the heat treatment?

 

[HSC ///]

Sounds good. If I may, would the cracking issue likely occur during the forging, or during the heat treatment?

this is what you are working with... I just don't see how you could move the core evenly and thicken it in a way that you need. I certainly don't know how to do it

I think cracking would most likely occur at forging, if your forge temp is too low...I've never cracked a blade of this laminate during heat treat.

 

[musicman980]

this is what you are working with... I just don't see how you could move the core evenly and thicken it in a way that you need. I certainly don't know how to do it

I think cracking would most likely occur at forging, if your forge temp is too low...I've never cracked a blade of this laminate during heat treat.

Thank you very much for that pic, I don't see many of them or finished projects with them outside of stock photos.

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[Stacy E. Apelt - Bladesmith]

For a chisel you really don't want san-mai ... you want ni-mai. The hardenable metal is on the one side and the showy metal on the other. The best way to get that is have someone forge weld your piece of steel onto a 1/8" thick bar of Hitachi Blue steel. This will give you a nice thick billet that will have hard steel for cutting on the ura, and pretty steel for the omote. The old core will show as a bold stripe across the chisel just a bit up from the hard steel edge.

I can't speak for him, but I bet HSC would do the weld for you for a low price. If you need the piece of Hitachi blue (or white) for the billet, I will send it to you.

 

[musicman980]

https://i.imgur.com/RzNfgxJ.jpg

Here's the grind I am trying to achieve, at least for the paring chisels. I might give it a try in a couple months, as I don't have my tools on me. As long as I can keep that core reasonably straight while swelling the billet 1-2mm I'll be in business!

 

[musicman980]

For a chisel you really don't want san-mai ... you want ni-mai. The hardenable metal is on the one side and the showy metal on the other. The best way to get that is have someone forge weld your piece of steel onto a 1/8" thick bar of Hitachi Blue steel. This will give you a nice thick billet that will have hard steel for cutting on the ura, and pretty steel for the omote. The old core will show as a bold stripe across the chisel just a bit up from the hard steel edge.

I can't speak for him, but I bet HSC would do the weld for you for a low price. If you need the piece of Hitachi blue (or white) for the billet, I will send it to you.

I just missed your post, Stacy, thank you very much for the offer. I'll make the final decision in a few months time, I appreciate everyone's thoughts.

 

[weo]

Not sure if you got the answer to your question about what happens when you forge the billet on edge to try to thicken your bar. With a thin stock on edge you get a mushrooming effect where the edges will thicken more than the center and or bend the bar causing the uneven forging Stacy was talking about

 

[musicman980]

Not sure if you got the answer to your question about what happens when you forge the billet on edge to try to thicken your bar. With a thin stock on edge you get a mushrooming effect where the edges will thicken more than the center and or bend the bar causing the uneven forging Stacy was talking about

Yeah that's definitely a concern of mine, especially with a 1" wide chisel. Now I have seen Japanese chisels with higher sides, with a sort of concave top, but I'm hoping the smaller width chisels won't have too much, if any mushrooming. :/

If I have to let these things cool down after each hammering just to see where the core is at, I'll just make something different lol.

 

[musicman980]

Here's a rough idea of a half inch wide piece of the billet with it's thickness of 5.5mm (solid line) turning into a 1/4" chisel with a thickness of 7.5mm (dotted line), just to better illustrate my intentions. This is turning out to be unknown territory...

https://imgur.com/a/CAciM3g

 

[Stacy E. Apelt - Bladesmith]

Easy with CAD, hard with metal and a hammer.

The chisel diagram you showed has the core at an angle down the blade. To get that from a center core billet you would have to grind a taper down one side end to end. Think how much stronger the cutting tip will be with it backed by hard steel, not soft suminagashi. The hardcore will also be pretty thin in that chisel. It would be much more robust in ni-mai. IIRC, Workshop Heaven sells the stuff you want. It is pure iron and whitesteel ni-mai. for making plane irons and chisels. Again, you can have it made up much easier and cheaper than ordering from them. Save that piece of suminagashi for a nice kitchen knife or tanto ( what it is meant for) and get/make a billet for your chisel. If you don't need suminagashi, pure iron or WI over a high carbon steel like W2, 1095, Hitachi blue/white makes a very traditional chisel. This gives a tough body with a very hard and sharp edge.

If you don't get any offers, I would be glad to make up a tapered ni-mai suminagashi bar. You could then easily forge the bar into the chisel shape desired with an integral bolster and all. I would leave a soft steel round tang on (from the handle bar) so you could make the chisel a through tang for mallet/hammer use. This thread has me thinking of making up some billets for cool chisels, anyway.

 

[weo]

If it's a chisel you're after, then I'd do what Stacy recommends and use this billet for a knife blade.

But back to the original question, yes, it can be done, but not easily. You'd want to upset the bar enough to give you enough thickness that you can then forge the width to the blade to. You really have to overshoot your dimensions on the first upset. I'm not sure I know anyone who could forge that into the final dimensions without upsetting the bar.

 

[musicman980]

Easy with CAD, hard with metal and a hammer.

The chisel diagram you showed has the core at an angle down the blade. To get that from a center core billet you would have to grind a taper down one side end to end. Think how much stronger the cutting tip will be with it backed by hard steel, not soft suminagashi. The hardcore will also be pretty thin in that chisel. It would be much more robust in ni-mai. IIRC, Workshop Heaven sells the stuff you want. It is pure iron and whitesteel ni-mai. for making plane irons and chisels. Again, you can have it made up much easier and cheaper than ordering from them. Save that piece of suminagashi for a nice kitchen knife or tanto ( what it is meant for) and get/make a billet for your chisel. If you don't need suminagashi, pure iron or WI over a high carbon steel like W2, 1095, Hitachi blue/white makes a very traditional chisel. This gives a tough body with a very hard and sharp edge.

Exactly, the taper down to one end. I never considered that that would compromise the strength of the edge itself, I just thought it would be supported enough by the core running *not* perpendicularly to the angle of attack. But now that you mention it, it sort of makes sense that my chisel design would be less robust, since the edge itself would be pushing more directly upwards into mostly soft suminagashi, while still also pushing, albeit to a lesser degree, on the diagonal running core. That's what you mean, right?

If you don't get any offers, I would be glad to make up a tapered ni-mai suminagashi bar. You could then easily forge the bar into the chisel shape desired with an integral bolster and all. I would leave a soft steel round tang on (from the handle bar) so you could make the chisel a through tang for mallet/hammer use. This thread has me thinking of making up some billets for cool chisels, anyway.

You wouldn't even have to taper it if that would be easier for you. We'll PM

But back to the original question, yes, it can be done, but not easily. You'd want to upset the bar enough to give you enough thickness that you can then forge the width to the blade to. You really have to overshoot your dimensions on the first upset. I'm not sure I know anyone who could forge that into the final dimensions without upsetting the bar.

Ah yes, that's the word, upsetting. It would be upset from the sides, not the end, to swell it by a few millimeters. Unless these chisels could be robust enough for even some paring, my idea seems to be dead. Who knows, maybe I'll get a bar in the future just to experiment and document.

Thanks all

 

[weo]

upsetting. It would be upset from the sides, not the end, to swell it by a few millimeters. Thanks all

Yes, but in order to accomplish what you are proposing, you'll need to do some upsetting from the end.