Sashimi knife project...

[Feukair]

Here's the one i made for myself by modifying a file.

Sen Draw Knife

[Feukair]

Well guys I tried to harden and heat treat this blade yesterday and it developed a severe crack about 3" from the tip during the quench. Heating blades for quenching is something I need much much much more experience at. (im still very new at all of this). I have developed some good patience while forging but I'm not there yet with the heating before quenching. I thought i had the front portion of the blade a little to hot but it was late in the day and i got impatient and quenched it anyway.

This is something i definitely need to work harder on. I've also collected almost all the parts i need to build a gas oven for heating the blades to critical temp with real control. I think i may wait until i build that before i quench another one.

Well, next weekend i'll start hammerin' out another one of these babies... ;-)

[markb]

Sorry to hear that Feukair, you had a lot of time in that blade and it showed.

What did you quench in and what temp. was it.?

[Dodge]

Feukair,
I'm just learning myself and your misfortune brought a question to mind. Did you normalize the blade before hardening? This is heating to critical and allowing to cool without quench to releases the stresses that builds up in forging. Some more experienced bladesters might correct me or perhaps fill in the gaps for me But I'm not even sure it has to be done with all steels. It was recommended for the 5160 I am using. the guy that supplied me the material suggested normalizing 3 times before I harden it.

[Feukair]

Originally Posted by markb

Sorry to hear that Feukair, you had a lot of time in that blade and it showed.

What did you quench in and what temp. was it.?

I only check the temp by testing with a magnet over and over until it goes just past non-magnetic. In this case the forward part of the blade came up to temp quick, then i went back in to get the part near the handle up to temp, which was pretty difficult because of my setup, and by the time i got the base up to temp the part about 3" from the tip got even hotter, i could tell it was hotter because it was brighter color. But like i said, i got impatient cuz it was getting late in the night and i quenched it anyway.

I've been collecting parts and various plans to build a electronically controlled propane forge/oven to use to heat the blades to critical temp.

I also don't have a very good setup for doing this. When i built my firepot i made it basically square, like a traditional pot, and that has turned out to not be a good design at all for knife making. Even if i meticulously work the blade in and out of the firepot the middle is always hotter than the tip or the base.

[Feukair]

Originally Posted by Dodge

Feukair,
I'm just learning myself and your misfortune brought a question to mind. Did you normalize the blade before hardening? This is heating to critical and allowing to cool without quench to releases the stresses that builds up in forging. Some more experienced bladesters might correct me or perhaps fill in the gaps for me But I'm not even sure it has to be done with all steels. It was recommended for the 5160 I am using. the guy that supplied me the material suggested normalizing 3 times before I harden it.

Hi Dodge, I'm pretty sure this one cracked because it was too hot in the area of the crack when i quenched. Another of my knives which i got, far along in the process of polishing, also showed a small hairline crack. At that time i remembered that the same thing occured in that area of that blade, a brighter color than the rest of the blade during the quench. So I'm even more frustrated with myself on this one that i let myself get impatient and did the same thing again. I was making this knife for a friend, and now he'll have to wait longer for his blade...

I did what i believe is called annealing... After forging i brought the whole knife up past critical temp (magnet test) and plunged it in a large bucket of ashes and left it until cool enough to handle, which takes quite a few hours.

I did not do what i understand to be normalizing. I was reading some on that this am. I believe normalizing is bring the piece up past critical then letting it air cool.

The reading I found this am recommended normalizing 3 times (as you say) and then annealing once. (by the definitions above) I've always annealed my blades after forging, i also anneal my metal (W1 drill rod) before working with it.

I'm going to take your advice and start normalizing 3 times and annealing. As you say, i don't know if W1 requires it. I'm no metallurgist but it seems to be a common recommendation in the bladesmith world so i suspect it would do less harm than good for any of the steels guys like you and me would use.

Thanks again guys.

[shaun]

dude that is a verry nice knife, good craftsmanship, i think an oak or ebony handle would look stunning on that blade.

[Rravan]

what are you uing as your quenching medium

[jimmy seale]

how do you harden.temper a sen? i would like to have one to use.i got a 4 x 36" belt sander/ 6" dics at Lowes for 100$ but i can't get very fine grits for it locale.

[offroadgreg]

Jimmy, I was inquiring on another knifemaking forum about making one of these for myself, and I was told that they are left fairly hard.. hard enough to crack if dropped! Im no expert tho so i cant tell you I've used it and it works.. but I am currently grinding one I forged the other day and Ii plan on leaving it hard to see how it works.

Feukair, that is/was a very nice knife you have.. excellent craftsmanship. hopefully the next one wont crack :O