HT thin kitchen knife

N

Natlek

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Jun 9, 2015
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There are already more than two years since I bought this steel and I was delaying making kitchen knife because of fear from wrapping . It is 1.1259 steel 2.2mm thick . Now I have one idea and I'd love to hear what you think about it ?
What if I grind blade and next I make two plate from steel /say 5mm thick and mount them with small bolt on blade blank to prevent wrapping when I do HT ? At the same time it may achieve some kind of differential hardening ? Something like on this drawing ?

jkwrig.png
 
I have no belt grinder , only file jig and disc sander for now , and I still learn how to use it . I want to grind almost a full flat ....... Personally I do not see any problem why I could not do like this , but I do not want to ruin steel .
 
The main reason for grinding after heat treatment would be due to the fact that you would not have enough material in the blade after shaping to keep the knife from warping substantially, particularly at the edges, especially if you are using thin stock and grinding it to an edge thinness suitable for kitchen knives. I suppose you could grind the bevels up half way to save yourself some work, but since you don't have a grinder that would be a moot point since your tools wouldn't really be suitable for post heat treat grinding.
 
What steel is it? If your bevels are even then you shouldn't have many problems with a regular quench. I do however think your idea will work.
 
If I'm not mistaken 1.1259 is just 1080-1084 right? Being .086 thick could be problematic on warping depending on a few things. Blade size is a big factor as well as making sure it is evenly heated to the same temp. Another thing that can affect warping is uneven edge bevels.
 
In my experience with thin steel you also have to worry about bacon edge if you grind too much off. You have less steel behind the edge than with even 1/8" steel and I've only had issues with it on thin kitchen knives. No way to stop that with a clamp on the spine.

Because of warping and twisting issues I only grind thin kitchen knives post heat treat now. And I really hate that much grinding post heat treat...

-Clint
 
I also grind most thin blades after heat treat especially fillet knives.
That being said a bowed or warped blade is easy to fix when tempering but not a bacon edge.
 
Generally under .100 but it all depends on blade length and width as well. I use alot of .072 and .090 thick 15n20 and that all gets ground after heat treat. If it's a short blade then no point in grinding after heat treat but generally you leave around .03 on the edge for heat treat so if you using say .072 thick stock that's not much you can remove befor heat treat. But I try and always give the blade a quick 45° angle down to my desired thickness. Thoes sharp corners after heat treat will really strip a belt quick.
 
I'm so sorry , I mixed numbers . Steel is 1.2519 . Sorry!! I have material for about 4-5 kitchen knives.All will be Gift for close relatives .One is for my brother, I have already bought expensive wood handle for his knife . So far I HT only one long and thin kitchen knife , but no high grind like I want to do this time ...... I need your opinion only what will happen with steel if I HT like this . I'm afraid that because of the thickness of the plate, that will carry a lot of heat on the thin part of the blade during hardening/quenching ? If wrap it s my fault :thumbup:
 
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Augus7us said:
In my experience with thin steel you also have to worry about bacon edge if you grind too much off. You have less steel behind the edge than with even 1/8" steel and I've only had issues with it on thin kitchen knives. No way to stop that with a clamp on the spine.

Because of warping and twisting issues I only grind thin kitchen knives post heat treat now. And I really hate that much grinding post heat treat...

-Clint
Click to expand...

Can you explain what is bacon edge ? I can leave extra steel on spine which would be easily to grind after HT ?? If that helps ? Steel I have is 2.2mm. X 50mm. X 1000mm.
 
Matt R said:
What steel is it? If your bevels are even then you shouldn't have many problems with a regular quench. I do however think your idea will work.
Click to expand...

Steel is 1.2519 and this steel like very , very thin edge ....say those who know much more than me .That's why I want a full flat grind , but wrapping is problem for me . I also think that this will work , but I'm not sure what will happen with steel during HT because of this two extra plate .......
 
Natlek said:
I have no belt grinder , only file jig and disc sander for now , and I still learn how to use it . I want to grind almost a full flat ......
Click to expand...
Do HT before grinding. Replace file in Your jig by angle grinder and You'll be able grind it after HT. If You don't have angle grinder just use power drill like here and here.
 
Natlek said:
I'm so sorry , I mixed numbers . Steel is 1.2519 . Sorry!! I have material for about 4-5 kitchen knives.All will be Gift for close relatives .One is for my brother, I have already bought expensive wood handle for his knife . So far I HT only one long and thin kitchen knife , but no high grind like I want to do this time ...... I need your opinion only what will happen with steel if I HT like this . I'm afraid that because of the thickness of the plate, that will carry a lot of heat on the thin part of the blade during hardening/quenching ? If wrap it s my fault :thumbup:
Click to expand...

I have used this steel a bit. grind till your edge thickness is 0.5mm. quench in oil till black then put it between two plates, put a weight on top and allow to cool. haven't had any issues with 1.2519 warping.
 
Blades will warp. that is just the way it is, you need to learn to straighten blades after hardening and after tempering.
 
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