270mm W2 Sujihiki!

Hey guys!

I thought I'd start a little build along thread for @NMaxy and his 270 Suji . Since you guys have seen dozens of forged and ground blades in my builds though...I figured I'd skip directly to the good stuff!



Clay layout! A little clay goes a long way my friends. Keep in mind also...if you're a bladesmith and are wanting to try similar patterns...it probably won't work out the same way. Differentially heat treating blades is all about thermal mass, the state of the steel prior to heat treat, and rates of cooling. My patterns work for me the way they do because of how my blades are setup to begin with. Everything from the geometry, thicknesses, rate of taper, and the structure the steel is in prior to heat treat has an effect on this. From there...temperature in the oven, duration of time the blade is left to soak in the oven, temperature when the steel hits the quench, angle of the blade being introduced into the quenchamt, rate of immersion, temperature of the quenchant, type of quenchant, how long the blade is held in the quench, and the pattern and thickness of the clay get to play their part. Changing ONE thing by the smallest amount...only changes everything.

If any of you are interested in learning more...by all means send me a PM. If you're a bladesmith having trouble with your own hardening procedure...I'm more than happy to help out!!


Directly out of the quench. That line is NO guarantee of a successful hardening lol. It's usually a good indication of what the line will look like if it WAS successful, but again...even that's not guaranteed. Differentially hardening kitchen knives is much like being married to a very beautiful, very intelligent, and very willful woman. What worked yesterday may or may not work today, and is almost guaranteed to be different than what works tomorrow. You're going to screw up more times than you do things right, and the main thing that keeps you at it is pure love, loyalty, and determination.

But man, when you get it right...it's magic .




Luckily, it worked perfectly this time . I posted three pictures so you could get a bit of a glimpse at the activity that will be present when this blade is polished out. This one's going to be pretty spectacular. I know, I know!!...I say that with every single one of them...lol. But hopefully so far you guys think I've been right every time like I do .

More to come as it happens!

 

WIP's never get old!

 

Very interesting comparison of the clay to the final hamon. Fascinating WIP, thanks Cris!

 

Thanks guys!

@zwiefel the clay is not a demarcation line between soft and hard like so many think. Rather, it interacts with the quenchant and steel as a sort of intermediary. It provides thermal mass to the steel, retarding the rate of cooling, and also affects the flow of the quenchant over the steel, again retarding the rate of cooling. Understanding this relationship can give you some insight into what the finished hamon will look like.

For example…this blade was quenched tip down. The line would look VERY different indeed had I quenched it edge down.

 

That's really fascinating....why tip down instead of edge down?

 

On this blade...because I wanted a certain effect. The quenchant swirling over the ridges of clay change the cooling rate both before and behind each ridge. Edge down would have made for a far different pattern, and probably would have had hardness contacting the spine all over, if it didn't mostly just through harden.

 

Oh, by the way...I cleaned up the profile.

On kitchen knives, I leave extra meat on the edge to help fight warpage and give strength to resist cracking. This...being a suji...started around 45mm at the heel. As it sits now, its a sleek 39mm, with a wicked profile taper and a looooooong...roughly 180mm...flat edge .





Next is grinding in the geometry, then polishing to bring out the hamon. Can't wait to see what she looks like with a full polish on it .

 

Thanks for the WIP Cris , I will hit you up later for hamons, your ones come out great

 

Very informative Chris,the endless variables must mean there is a lot of experimentation to get to where you can get consistent results?

 

Thanks man...and anytime!

Absolutely. Controlling all of the variables you possibly can (trust me...there's so many of them out of your control its not even funny lol) is the only way to start, and then you have to start tweaking them. Just last night I had two failures for what most would assume are no comprehensible reason. One of them I think I understand...the other I don't get, at all. I've got to get the kids to archery this morning, but I'll get some pictures up of the patterns this afternoon on my 'What's on my Bench' thread.

 

Love these threads! As we like to say" that ain't ugly" :cool1

 

Very Nice!

 

I could never get tired of watching/trading works in progress threads! This is great!

 

Thanks guys! I love sharing at least as much as you guys like watching...trust me, lol.

For example!




This is a quick etch at 120 grit just to see what the rough line looks like. And here's a short video:

http://instagram.com/p/vUQrc5GOsR/

I'm more than a little pleased .

The grind is actually almost done on this one by the way. I need to bring the edge down to .05-.08mm, round the spine and choil...then begin polishing. After that it's handle work...and done .

 

when we see the japanese honyaki blades the hamon is always so uniform and perfect. do you think with a ton of practice you will be able to do the same? or do they use a different process or something? either way it looks great!

 

Mine are the way they are by preference. I use the steel I do specifically to assist me in achieving the look I'm after. If I wanted an even perfect line as I've seen on the Japanese honyaki...I'd do things a little differently.

 

but it is in your power to do a perfect one? i guess what im getting at is, is it harder to do a perfect one?

 

Not harder. Just different.

Besides...what is wrong with these? I think they're closer to 'perfect' than a boring painted on line .

 

i like yours too i was just wondering on the differences. if the japanese could make cool ones like you do than why are theirs always perfect squiggles?

 

Mostly it's because Japanese are very minimalist I would think...and very much bound by culture. Honestly, my style of hamon (from my understanding in speaking with friends who are Japanese)...and even most other western maker's hamon...would be considered garish at the least...at the most even offensive to their culture and history. The Japanese ABSOLUTELY have the knowledge and skill to do what I do...they just don't...very often anyway. Here is an example of an actual nihonto (basically a sword forged in Japan by a master...typically antique) which shows much the same activity and structures:



They call this 'hitatsura' which basically means uncontrolled (not a literal translation I don't think...but it conveys the meaning well enough). Often it was done without any clay at all...or very minimal. Sometimes it was achieved with more clay.

Differential hardening is a science unto itself my friend .