I know there is a lot of confusion about differential tempering. It is done to soften the back more than the edge. it is not differential hardening. blade is fully hardened, differentially tempered for spring back and hard edge. It is usually then tempered in an oven to control the hardness of the edge. Leaves no visable temper line.
-
The BladeForums.com 2024 Traditional Knife is ready to order! See this thread for details: https://www.bladeforums.com/threads/bladeforums-2024-traditional-knife.2003187/
Price is$300$250 ea (shipped within CONUS). If you live outside the US, I will contact you after your order for extra shipping charges.
Order here: https://www.bladeforums.com/help/2024-traditional/ - Order as many as you like, we have plenty.
Picture of differential tempering
- Thread starter sabre
- Start date
- Joined
- Oct 16, 2001
- Messages
- 1,917
Thanks for the photos. Could you also post some information about how you do this and how you get the lines so even?
Thanks again,
John
Thanks again,
John
Mark Williams
Moderator
- Joined
- Nov 28, 2000
- Messages
- 4,760
Very nice pics,How did you keep the edge cool?Water bath?
Mark
Mark
- Joined
- Jan 16, 2002
- Messages
- 219
Here is my effort in selective hardening. I use the clay method which I belive gives me a little more control in what I want to do.
www.homestead.com/hvknives/knifeconstruction.html
www.homestead.com/hvknives/knifeconstruction.html
- Joined
- Jan 16, 2002
- Messages
- 219
I re-read the first post and now I don't understand. Selective hardening is just that. Selective tempering to me implies just that, don't at the tempering phase. Why would you selectively temper something and then temper in the oven?
- Joined
- Jan 16, 2002
- Messages
- 219
Also I guarantee if you took those blades to 600 and dipped in ferric the temperline would show because the ferric would attack the hard and soft steels differently. How you control the polish determines the temperline showing or not. Just my 2 cents.
- Joined
- Jun 25, 2001
- Messages
- 8,474
I use a water tube Like this, whether I dif, temper or dif Harden.
Tempering the edge after, tempers the edge to what you want it to be
tempering or drawing out the spine softens it at a lower Rockwell
toughness here is what ever you want it to be, it depends on the heat you use..
if the back is left dead soft in edge hardening the grain
will be bigger, if the hole blade is hardened and then the back is drawn
the grain should be smaller there-for making
the hamon harder to see. I hope this helps
Tempering the edge after, tempers the edge to what you want it to be
tempering or drawing out the spine softens it at a lower Rockwell
toughness here is what ever you want it to be, it depends on the heat you use..
if the back is left dead soft in edge hardening the grain
will be bigger, if the hole blade is hardened and then the back is drawn
the grain should be smaller there-for making
the hamon harder to see. I hope this helps
- Joined
- Jan 13, 1999
- Messages
- 1,422
Check this out:
Differentially hardened katana by Howard Clark, 1086M with clay and water.
"look upon my work, ye mighty, and dispair."
Differentially hardened katana by Howard Clark, 1086M with clay and water.
"look upon my work, ye mighty, and dispair."
- Joined
- Dec 4, 2001
- Messages
- 3,824
very cool blades everybody, I especily like the katana. The way I do it is with an edge quench with only the edge getting heated to criticle with a torch. I find that for my methods it gives me better control.
BB, the old time cuttlers used to take the straw color right to the edge. The extra temper in the oven is to make sure the edge gets the right time and temperature for tempering and is added insurance.
BB, the old time cuttlers used to take the straw color right to the edge. The extra temper in the oven is to make sure the edge gets the right time and temperature for tempering and is added insurance.
- Joined
- Mar 18, 1999
- Messages
- 2,112
Good example, Sabre!
I attended the same class that Sabre did and probably didn't learn as much! You can tell by looking at his knives, just awesome.
What we did was to temper the blade for an hour immediately after quenching then did the draw on the spine in a pig trough with a torch, then temper again for an hour. Pretty technical stuff!
I recall one fella (Myagi)in the class that did it this way and when he did the "bend test" on his blade, it came back to near straight after bending it 90 degrees in the vise. This blade passed the cutting tests as well.
Although simple to do, it accomplishes more than meets the eye. One thing that Roger Massey mentioned was that the blade needs to be cleaned up as soon as possible due to the part that was in the water will somehow etch and look pretty bad. Until you do this, you won't appreciate what he meant.
C Wilkins
I attended the same class that Sabre did and probably didn't learn as much! You can tell by looking at his knives, just awesome.
What we did was to temper the blade for an hour immediately after quenching then did the draw on the spine in a pig trough with a torch, then temper again for an hour. Pretty technical stuff!
I recall one fella (Myagi)in the class that did it this way and when he did the "bend test" on his blade, it came back to near straight after bending it 90 degrees in the vise. This blade passed the cutting tests as well.
Although simple to do, it accomplishes more than meets the eye. One thing that Roger Massey mentioned was that the blade needs to be cleaned up as soon as possible due to the part that was in the water will somehow etch and look pretty bad. Until you do this, you won't appreciate what he meant.
C Wilkins