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Carbon steel - Work hardening?


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Hi guys,

 

I was going to put the finishing touches on my latest dagger yesterday, but had to give up as the steel frame and spacer had apparently work-hardened from being dead soft, to between 55 and 60 HRC after being worked on by angle grinder and belt grinder.

 

Is this even possible? :o

 

I glued the handle parts together, and then started removing surplus steel from all angles as I honed in on the final handle shape.

 

When I started engraving the graver point kept breaking again and again, after not even 1mm if cutting. I then noticed how my scribe also didn't want to scratch the metal - which is unusual.

 

Is it really possible to steel to work-harden to such a degree?

 

The steel composition is unknown, but it is from an old circular sawmill sawblade. Same as I used on my previous dagger actually...

 

Sincerely,

Alveprins

Stål Tann 001.jpg

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I wouldn't think you could work harden it that much.  Perhaps you have run into a layer of carbide?  Or was it possibly hardened and it had a layer of decarb making you think it was soft?  

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I have heard of 300 series stainless steels work hardening from grinding, but I have never experienced it myself.  Was the last belt you used on the dull side by any chance?

 

That is another stunning knife.  You've shot way past being a contemporary of mine to being an inspiration.

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-Brian

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18 hours ago, Jerrod Miller said:

I wouldn't think you could work harden it that much.  Perhaps you have run into a layer of carbide?  Or was it possibly hardened and it had a layer of decarb making you think it was soft?  

 

Hi Jerrod, thanks for the feedback! :)

 

Well, I used my "Tsubosan" HRC measuring files to test the hardness on both the steel spacer, as well as the entirety of the frame going around the handle. Only the 55HRC file managed to bite - very slightly, while the 60HRC effectively bit. I tested with the 55 file several spots on both sides - and result was the same.

 

This spacer and frame is a simple cut-out from a large round sawblade from an old wood-mill. So I don't think it is simply a layer of carbide.

 

I softened the steel by heating it to above critical, and letting it cool down to room temperature. I did this once before cutting them into their basic shapes, then again before machining them to absolute minimum measurements, and then again before assembling the handle in its entirety w. epoxy and pins.

 

At this stage the handle shape was as close to the planned size of the handle as I could get. I then proceeded to working it on the belt sander - making sure to not letting it overheat (taking care not to heating the epoxy too much) throughout shaping it to final shape. 

 

Then I proceeded with files. At this stage my wood files didnt have much bite (I figured they were just dull) so I used diamond files instead - which worked well.

 

In regards to there possibly being a layer of de-carb - I've removed way too much steel for that to be a possibility. :) 

 

17 hours ago, DanM said:

What graver steel are you using,do you dub the point?  https://engraverscafe.com/threads/dubbing-the-point-of-a-graver.26869/

 

Hi Dan, thanks for the pointer! :)

 

I use Lindsay Carbalt (Carbide), M42 steel and HSS graver points. In this particular case, the carbide point was the only one that would even bite. The M42 and HSS just skid right over. M42 tip simply just broke if I started in an already established channel from the carbide tip.

 

I do not dub the point, but from reading your link - this is definitively something I am going to try out as I have a sad tendency to break the tips - especially of the carbide ones. ;) Thanks!

 

As for not dubing the point in this case - that would not explain how I was able to do extensive engraving without issues on my previous dagger, which used steel from the same saw-blade. (which leaves me puzzled as to how this happened... :wacko: )

 

15 hours ago, Brian Dougherty said:

I have heard of 300 series stainless steels work hardening from grinding, but I have never experienced it myself.  Was the last belt you used on the dull side by any chance?

 

That is another stunning knife.  You've shot way past being a contemporary of mine to being an inspiration.

 

Hi Brian,

 

I suppose the belt perhaps was somewhat dull... I kept the workpiece relatively cool though - not letting it overheat.

 

And thank you for your heartwarming comment! :) Actually, I lost my job of 10 years not long ago - so I am now forced to make this a full time thing - which will further accelerate my skills. I find myself at an exciting (and nerve wrecking) time! ;)

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sounds like it air hardened.

 

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Jake Cleland - Skye Knives

www.knifemaker.co.uk

"We can't solve problems by using the same kind of thinking we used when we created them."

"Everything should be made as simple as possible, but not simpler."

"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."

 

Albert Einstein

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9 hours ago, Alveprins said:

I find myself at an exciting (and nerve wrecking) time! ;)

You’ve got this mate. Just keep going.

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"The way we win matters" (Ender Wiggins) Orson Scott Card

 

Nos, qui libertate donati sumus, nes cimus quid constet.

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