View Full Version : More beginning questions about hamon
10-22-2011, 10:48 AM
I have a customer who is crazy enough that he wants me to try hamons on some of his blades, knowing full well I have never (deliberately) done hamons. (I did get one unplanned on a thich chopper - just because the monster blade was too much for an even quench.
I have read Stephan Fowler's awesome tutorial, and it raises some questions - as most good learning experiences do.)
Is it reasonable to go to 400g finish pre HT. I understand good hamon steels are shallow hardening, so I'm guessing you don't want to sand it all away.
For learning - 1095 or W2?
I see no indication of temper. I understand the soft spine should help protect against breakage, but what prevents the edge from chipping if it is full hard?
I use Haughton Quench K (a 9 second oil) -= presume it's fast enough? Sections would be likely 1/8 or 5/32.
I supect ther'll be more questions. Any suggestions or opinions much appreciated. (as well as prayers for my customer's blade). :3: He hasn't started it or even chosen the steel yet.
10-22-2011, 12:18 PM
Knife blades made from a shallow hardening steel do not form a jacket of martensetic steel around a core of pearletic steel as will happen with a steel rod or block. It will only form martensite to a thickness of twice the depth or hardening. Thicker than that the steel will form pearlite. If the steel will only form martensite to a depth of 1/32", for example, it will only harden the blade where it is 1/16" or thinner. Thicker than that pearlite will form. Remember that this does not only apply to the edge of the blade but to the corners of the spine as well. You also need to control the grain size as depth of hardening increases with it. The only time you need to worry about grinding away the martensitic steel is if you have over refined the grain and you grind it away while sharpening the edge. From what I understand, this rarely happens. You have to get carried away with grain refinement.
I would choose neither 1095 or W2 for the strongest hamon. I would go with something in the line of 1050-1070 with a lower manganese level. The lower carbon content will allow more ferite to form, both within the pearlite and outside the pearlite, to promote differential etching. Those steel will work but the difference in the etch will not be as great. I've even seen pictures of a quench line in 9260 but I don't think I would go with it for a good hamon.
The clay coating will cause the formation of ferite and pearlite in the spine and the ishi lines. Besides, the differential hardening of the shallow hardening steel will also have this effect. Temper pretty much as you normally wood.
Match your quenchant to the steel that you are using. You might even have to consider water or brine.
10-22-2011, 11:32 PM
Thanks for the response Doug. For a minute, I thought you were yanking my chain about the 2 x depth thing - but I guess that would explain the unintended hamon that both Aldo and I have experienced.
How 'bout Aldo's 52100? Also pretty low manganese I believe.
Lots of steel here, but not much medium carbon (except some damascus I bought years ago thats mostly old manhole covers stolen off the streets of Mumbai... ) :)
10-23-2011, 01:59 PM
Aldo's 52100 is also pretty high in chromium and in carbon. You might get a quench line if you edge quenched it but I doubt if it would be very strong. I think that it is too deep hardening for a clay coating to delay conversion products austinite long enough for pearlite to form.
I found that thing about a knive blade hardening to twice the depth of penitration with shallow hardening steel a little mind boggling when I read it in Steel Metallurgy for the Non-Metallurgist by John Verhoeven myself. He said it was explained by film heat-transfer control. I decided to take his word for it because he already had my head spinning.
As far as the steel goes, I think that Admiral Steel carries 1050 in their regular catalog, as opposed to their knife steel catalog. I have no idea what it would cost cut to widths you might want to buy in small quantities. They carry 1075/1080 in the knife steel catalog plus 5160. They even have 9260 listed with their 5160 in two widths. I think that Kelly Cupples carries 1065, go to High Temperature Tools and Refractory and click on the steel bar there for a link to Cupples. Aldo carries 1070 which I immagine is lower in manganese because I understand that he recommends water quenching.
10-23-2011, 02:26 PM
Knife maker Doug pretty much laid it out for you , he knows what he is talking about . Although I have had good luck doing
hamons on 9260 steel from admiral, It could just be my clay recipe though ... Bubba
11 in. tanto from 9260
10-24-2011, 10:19 PM
Stock is hard to find. Admiral has never been good at supplying anything with consistencey - though I do have a couple pieces of their 1075/1080. Kelly Cupples doeasn't have any 1065 under 1/4". Checked USA knifemaker - Jantz - ellis (or whatever their new name is) - and more without luck. Aldo's 1075 is all 1/4"+. Thinking I may have to try the Admiral 1075/1080.
Time to stop whining and put something to the grinder I guess.:3:
10-25-2011, 07:18 AM
Knifemaker, I have real good luck with Admerial's 1075/1080. Useing M-C 11 sec oil with santinite clay.
10-25-2011, 06:56 PM
Good to know that I don't have to doubt the steel. If anyone else knows of a source of 1060(ish) bar stock in say 1/8 or 3/16, please let me know. I had a pound of satanit, but gave it away. Was thinking of using a base of ATP641 and some stove cement, but why re-invent the wheel.
10-25-2011, 09:08 PM
Furnice patch works fine. When I was at the hammerp-in people were doing hamons with some that had been thinned down a little with water and had some powdered charcoal mixed it with it. They put it on and stuck the blade in the forge with it still wet. It stuck just fine to the steel and produced some nice hamons.
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