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I Forge Iron

EB Pointed Knife


EduBacha

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Hello steel lovers, 

This is my second post, and I brought a knife that I finished yesterday. Hope you enjoy it. 

Made with: 

Steel SAE 1070 
Total length= 20cm ( 8') 
Blade length= 9cm ( 3,5') 
Handle length= 10,5cm ( 4') 
Thickness= 3mm ( 0,120')

Handle was made with a wood called "Pau-Ferro" here in Brazil. this is a link of the tree Caesalpinia paraguariensis 

Quenching = With the steel at 800ºC ( 1472ºF)  I quenched it into a mixture of 2 parts of water and 1 part of oil. 
For the tempering I left the blade for 1 hour at 260ºC ( 500ºF) 

PHOTOS: 
foto5-10_zpscef34590.jpg

foto2-15_zps86cfe881.jpg

foto3-28_zps3ee642be.jpg

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looks very "usable" (high praise in my book).  If you want to dress it up a bit the saddle on the top of the blade right in front of the handle---where your finger might rest in some uses---you could do a bit of fancy file work there which would both provide a better "grip" and make it a tad fancier.

 

I would have though that 500 degF might be a bit warm for tempering 1070 unless you were going for a quite tough blade and easy to sharpen.

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Thank you Thomas and Steve. 
It's very common here in Brazil quench with oil AND water, it's because the water at the bottom, has a higher specific heat so you can left the blade for a longer time into the solution and the temperature balances slower. 
There is a lot of physics behind this act, basically the oil quench slightly the steel and the water provides a second but faster contraction of the molecules of the steel. 

The temperature of 500ºF for tempering is not that high, we know (because of the graphics) that the real profitable tempering happens in the first 30 minutes of heat on the blade, so we put the steel at 500ºF and left it into the oven for a short period of time. 

But we do not follow the time and chart because every knife is different from each other, so we prefer to pay attention at the color of the steel, when it's light gold, it's time to turn of the oven and wait. 

But I am a learner and I feel good to recieve this questions and suggestions. 
Thanks a lot, 
EB. 

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The oil over water is a method used by some to avoid cracking when quenching a blade that would profit from a commercial fast quench oil; but such cannot be sourced for one reason or another.

 

If you are not allowing a blade to come all the way up to the temperature of the oven then you are not "tempering at 500 deg"

 

Please see http://en.wikipedia.org/wiki/Tempering_(metallurgy)#mediaviewer/File:Tempering_standards_used_in_blacksmithing.JPG

 

where light gold is more of a 400 degF temp.

 

And yes doing multiple tempering cycles is much more effective than doing one for a longer time

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Thanks very very much Benton!
I didn't know the Sharpfinger mentioned but looking for a while we can see somethings in common. 
 

Thomas, I liked the picture of the color of the steel with different tempering. But the light gold that I said is something between the 440degF and 500degF, after seeing the picture maybe it's convinient to say that it's not THAT light. sorry about that. But my oven was set up to 500ºF, it's not a professional oven made for blacksmithing. I left the blade there for 40 to 55 minutes only and I already got the color of gold. 

Btw it ends on a very sharp knife, easy to sharp but with a good durability on the edge of the knife. When I took it away from the oven and tried to remove metal to create the edge, my file barely removed metal, showing that the steel was a bit hard yet. 

Thanks, 
EB.

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we have a saying "the proof of the pudding is in the eating"  So if the blade works as you intended then the heat treating was "correct".

 

BTW here in the USA ovens often can be quite a bit off from what the dial says and we advise people to get a second oven thermometer to place in the same general area where the blade will go to doublecheck.

 

Also that is why I referenced that site as people see and describe colours differently---far better to have a reference source everyone can look at.

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Thanks very much rockstar.esq !  My logos shapes are made by hand because here in my city don't have anyone that could make it in adhesive, they said that it is too small to be shaped by the machines. 

ThomasPowers, I tried to find a thermometer that could read hight temperature scales, even on ebay but I didn't found it. I am sure that if I had one of this the work would be a lot more accurate. 

Thanks, 
EB. 

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