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Can hardened O1 be peened?


JohnCenter
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I want to try and make a puukko using O1 and a stick tang design similar to the Polar's and Laurie's that are sold by Brisa. I have my steel heat treated by  a local professional (digital oven, etc.). As a beginner,  I assume this means the stick tang as well as the blade will be hardened when done (59-60 Rc.). I don't know a lot about this kind of thing, but  I remember reading that most puukkos are hand made so the tang is often left softer than the actual blade.

If that is the case, will I be able to peen the hardened O1? Or do I have to request the heat-treater do something specific?

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01 is not very forgiving to peen at best, and hardened would be next to impossible.  Ask your guy if he hardened the whole thing or left the tang soft.  If he did the whole thing, your best bet would be to wrap the blade in a wet cloth and use a propane torch to draw the temper of the last half-inch or so of the tang.  Bring it to a low red heat and let it cool slowly.  This is a subcritical anneal and will make it as soft as it's going to get at this stage.  

Good luck!

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Chances are also really good that the forging of the tang caused some strange things to happen in the tang steel and even  a drawback like Alan suggests could be dicey.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

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9 hours ago, Gerhard Gerber said:

I could not get O1 annealed for love or money to drill tang holes

O-1 is hyper-eutectoid and takes a pretty controlled process for a spherodizing anneal.  You have a computer controlled kiln I think, so this process should work.

 

3 hours ago, Alex Middleton said:

You could always leave the O1 portion of the tang short, and then weld on an extension of mild steel.

This is a good idea. You could also braze in a piece of softer non-ferrous to accomplish the same thing.

Edited by Joshua States

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

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  • 3 years later...

It has been a long time since I posted, but I've continued to dabble in knifemaking with some success. But only 3 piece sandwich style knives. I hope no one minds me bumping my own thread, but I still have an interest in trying a Nordic style knife and wanted to revisit this topic.

 

What I understand from looking back is that O1 is not eaisly annealed once hardened but I may be able to anneal the end of the tang enough to peen? (Gerhard had no success)

 

Brazing is not an option for me at the moment, but I would like to try Alan's advice on the tang of a scraped knife. It is O1 hardened to 59-60. So are these the correct steps: I  protect majority of knife and use a common propane torch to heat the last 1/2" or so to red and let air cool. Do I repeat the heating and cooling, or is once enough? After that I tap lightly with hammer for a long time? It's this simple?

 

Am I being to optimistic in my revisiting this thread? Am I wasting my time?

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While I can't promise success, if you wrap the blade and first part of the tang in a wet rag, heat the end of the tang to red and hold for a minute or two, then slowly pull the torch back so just the tip of the flame is on the tang. Let it cool slowly until it's just barely red in a dark room. Hold as long as you can. Slow cool in ashes or vermiculite, making sure the blade as staying cool.  Now, polish the end of the tang. Hit it with the torch again (carefully and from a distance!) and watch the temper colors. Take it through all the colors, past all the blues to dark gray, just before it starts glowing, and let cool in still air.

 

This is a half-assed anneal followed by an overtemper.  This will get it as soft as it's going to get without a kiln.  Which may or may not be enough to peen...  only one way to find out!

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I was just about to suggest cut a keyhole in the tang and a key from threaded rod, when I remembered O1, peening or cutting a keyhole would be equally impossible.

 

I made 4 cleavers from bar stock O1 not too long ago and they are performing great, but I will never forge O1 again.

 

Not 100% sure but I think I got the idea for the keyed threaded rod tang here, used it once on a 52100 blade made from a single ball bearing and I ran out of steel for the tang........worked a treat. 

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On 3/8/2022 at 7:00 AM, JohnCenter said:

Brazing is not an option for me at the moment,

I take it you don't have MIG welder either? If you do, or at least have access to one, cut the tang short with an angle grinder and MIG weld a piece of mild steel to peen the end.
My best advice is simple, Finish this blade with a typical hidden tang handle and ........

Make another knife into a Puukko using a more forgiving steel

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

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Thank you everyone for the followup advice.

 

Alan, I will try your method and report back.

 

Joshua- I'll just be blunt and ask politely from those who know more than me- Can you please explain how a beginner using stock removal method and sending out for heat treat should go about producing a blade that can be peened?

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2 hours ago, JohnCenter said:

Can you please explain how a beginner using stock removal method and sending out for heat treat should go about producing a blade that can be peened?

 

Not Joshua, but my answer would be don't use O-1 or any other not-easily-annealed steel. That includes 5160, all stainless, and pretty much anything that's not a straight carbon steel, 15n20 excepted.  

 

1075 would be perfect for this.  The HT service will return you a hardened blade, you then dunk said blade in a can of water and heat the end of the tang you want to peen with a common propane torch until it glows red.  Walk away and let it cool to room temperature.  Done.  

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What Alan said. Stick with the 10XX series of steels, excepting maybe 1095 because it can be a little finicky.

Another option is to invest in a decent silver or brass brazing torch. Learning how to braze a softer metal onto the tang so you can add a pommel cap with a peened block or tang will allow you to do this and up your game in the handle making arena.

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

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  • 3 weeks later...
On 3/14/2022 at 3:29 PM, Alan Longmire said:

 

Not Joshua, but my answer would be don't use O-1 or any other not-easily-annealed steel. That includes 5160, all stainless, and pretty much anything that's not a straight carbon steel, 15n20 excepted.  

 

1075 would be perfect for this.  The HT service will return you a hardened blade, you then dunk said blade in a can of water and heat the end of the tang you want to peen with a common propane torch until it glows red.  Walk away and let it cool to room temperature.  Done.  

 

15n20 would work? What about 80CRV2? Would it fall in the same category as the 10XX steels in ease of annealing?

 

I tried the torch on a scraped blade of O1 and had some success. It peened over with patience, but the edges of the mushroom cracked. I'm going to grind it off and try again and see if I get the same results.

 

On 3/14/2022 at 9:18 PM, Joshua States said:

What Alan said. Stick with the 10XX series of steels, excepting maybe 1095 because it can be a little finicky.

Another option is to invest in a decent silver or brass brazing torch. Learning how to braze a softer metal onto the tang so you can add a pommel cap with a peened block or tang will allow you to do this and up your game in the handle making arena.

Up my game? Are there other advantages to brazing soft metal onto the tang then easy peening? What would they be? Isn't it a weaker link in the handle?

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1 hour ago, JohnCenter said:

15n20 would work? What about 80CRV2?

 

15n20 yes, 80CrV2 no.  It's basically super 5160 and doesn't anneal easily.  Simple steels only!

 

1 hour ago, JohnCenter said:

Isn't it a weaker link in the handle?

 

Nope.  If you do it right, brazing is stronger than the metals being joined.  The actual tensile varies depending on the braze composition, but it's typically 70,000 to 80,000 PSI, equal to welding with 7018 rod or better.  Brazing is not soldering.  Solder is just metal glue, a surface bond only.  Brazing involves the braze metal getting into the grain of the steel. Intergranular penetration.  Can't be removed without taking the steel with it.  

 

1 hour ago, JohnCenter said:

Are there other advantages to brazing soft metal onto the tang then easy peening?

 

The ability to add a stub of all-thread to a high-carbon tang is a great benefit for getting a tight fit.  If you use a peen block, you can thread it and use it as a nut to pull everything tight before peening the threaded tang, which then becomes invisible.  Leaving it a nut makes for easy disassembly if you prefer that.  

 

Brazing is also great for making sheath hardware, guards, handle frames, hollow pommels, studs, jewelry, shop tools, and anything you'd like to weld but that's either nonferrous or too small to use a welder on.  Jewelers' "hard solder" is a braze.  It's just a good technique to have at your disposal.  

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What Alan said times two.

 

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

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