knife making question

[Pat B]

  Jonathan gave me an anealed edger blade to make a couple of knives from. I cut out 2 blanks and have shaped one top into a knife. I need to temper the knife again but not sure how. I think someone told me to put it in the oven at "X" temp for "X" hours. While cooking my pizza for supper tonight I placed the knife in the oven(425 deg(F) and after getting my pizza out left it there for 2 hours at 450deg. I just turned the oven off and plan to let it cool slowly.
  Any help or suggestions would be appreciated. 

[cowboy]

I sure wanted to help ya out Pat but i'm not the authority on knife making . Seems like your suppose to quench em after they get hot to temper the steel or let em cool naturally to normalize em - just rambling. How ya doin? .

[El Destructo]

Place the blade in the oven at 550 degrees Fahrenheit for skinners.... tactical knives..... and meat carvers.

Observe the knife blade color between tempering cycles.... A harder knife will be straw color to brown.... mid-range would peacock to purple... and dark blue would be used for the softest blades.... There is a point of diminishing returns.... however..... If the blade color goes past dark blue.... the knife will begin losing temper and become soft...... The steel will need to be rehardened before you can continue.

Heat the blade at the desired temperature for one hour, and then allow it to cool to room temperature.

[Pat B]

Doing good Paul. How about yourself?  Haven't seen you around much lately. Working too hard?

  Thanks Mike. My oven won't go to 550.      Will the 425 for 2 hours help any?

[cowboy]

Thinking too hard mostly - I think . All is good. Looks like Mike has it figured out if you can ramp that oven up some .

[El Destructo]

Pat...watch the Colors in the Blade...if you can only get 450...so be it...that will make a nice Blade ...that will be easy to put an edge on...but it won't last as long as a Harder one...really I prefer one that isn't too damned hard anyways....go for it.

[Pat B]

Thanks Mike. I'll see what I've got in the morning. 

[nclonghunter]

Hey Pat,  if you cut and shaped the metal then I would suspect that the blade was in a soft form. Normally the steel is softened by heating it red hot and slow cooling in sand. After shaping then the steel is again taken to red hot and quince in water to harden. The oven temp and cook time is to soften it again to the temper or hardness you want for what you are doing with it. The temper is based on the carbon and type of metal.

Doesn't really give you the answer you want, but if you can find out exactly what the metal type is then the correct temp and cook times can be found.

check this link....http://www.technologystudent.com/equip1/heat1.htm

If you work on a blade that is already tempered then shaping it without burning the steel is critical. If shaped in this manner then no tempering is needed, just put handles on it.

[Pat B]

The metal I'm using is an edger blade that Jonathan annealed and gave me. I cut out the shape with a cold chisel so it was pretty soft. I did most of the shaping with a file but I did use my 6"x48" belt sander but didn't over heat the blade.
  I took the blade out of the oven late last night after it cooled. It was a tan color and with a few licks with a file the edge got shaving sharp. I've attavhed the handle scales with epoxy and will shape the handle and add brass pics today. I'll add pics when I'm done.
  Thanks for the link, NC.    I'll check it out. I am limited to not having the proper tools or a kiln for heating to proper temps so I'm working with what I have on hand. If I get further into this I will make a small kiln(a few fire bricks and a propane torch) and get the other tool necessary to build proper knives.
  Thanks for the help guys. I can see this will be a fun project...as if I need another!!! 

[don't cry wolf]

what you gotta do is:
1. heat it up red hot about 1485 degrees until a magnet wont stick to the metal ( acetaline torch or forge is needed )
2. plunge it  strait down into 150 degree vegetable oil ( this quenches or shrinks the steel hardening it )
3. after quenching a file shouldnt scratch the steel, buts its really brittle like glass
4. bake it in the oven at 500 degrees for an hour ( you need to back off the temper some because the steel is too hard and too brittle )
5. if its still too hard after cooling you can repeat step 4 again

as far as i know this is whats gotta be done to "temper" the steel

[R H Clark]

what you gotta do is:
1. heat it up red hot about 1485 degrees until a magnet wont stick to the metal ( acetaline torch or forge is needed )
2. plunge it  strait down into 150 degree vegetable oil ( this quenches or shrinks the steel hardening it )
3. after quenching a file shouldnt scratch the steel, buts its really brittle like glass
4. bake it in the oven at 500 degrees for an hour ( you need to back off the temper some because the steel is too hard and too brittle )
5. if its still too hard after cooling you can repeat step 4 again

as far as i know this is whats gotta be done to "temper" the steel

That's it in a nut shell. I'll only add that I like to make knives from known steel.Steel is fairly cheap and a lot of work goes into a knife only to be wasted if your steel won't harden properly because of too low carbon content.Kinda  like making a bow out of a wet willow branch.

[rover brewer]

what lonewolf said is right, the magnet is a good idea its how I heat treat mine, when the magnet no longer is drawn to the metal its ready for quenching it would be a good idea to have a telescopic magnet.

[don't cry wolf]

I'm pretty darn sure too if you want to get more carbon into your steel, you gotta leave it red hot in the coals for a long time ( but make sure your fire aint too hot that steel is gonna burn up ) then quench it. what this does is lets the steel expand, the carbon from the coals will get into the steel and quenching it traps the carbon in the steel when it shrinks from the quick cooling.

[Pat B]

The steel in these edger blades is tempered when you buy them. They have to be annealed to work them and re-tempered after. I'm sure it is not the best choice for knives but for a beginner it works very well.
  I also have some pieces of large industrial band saw blades but I want to get the hang of knife building before I jump into them because I don't want to mess them up.

[R H Clark]

A piece of 1095 carbon steel  1/8"X 1-1/2" X 36" is only $14.Well worth it IMHO.Scrap steel is fine if you are using it for the spirit of it.Maby a dear friend gave you a piece and that's fine but with known steel you take away all the guess work.

Usually by the time I finish a knife I've got so many hours in it,it's worth using $5 worth of good steel.