260(ish)mm Gyuto WIP

We're going to do this one a little differently folks, as this blade isn't finished yet. This is also the format (WIP) that custom order blade posts will take in my section as well (this isn't a custom). I like to document a persons knife being made with pictures. Partially because I think it helps with the wait...but also because I think it helps bring the project into a bit more personal space for the new owner than just plunking down cash, waiting, plunking down more cash...and receiving a finished blade in the mail a month later.

That said...here we go!

It had admittedly been awhile since I'd made anything when I decided to go full time making knives. I have a wait list for custom orders, and had contacted each person on that list in order to verify...but I really just wanted to get out there and DO something. So...I did.

And this is where they all start, lol:


And a few hours later, we usually have something like this:


Spine up:


Edge up:


In this picture, you can see just how much the blade is thinned with the hammer. All of it is done by hand:


Beginning to grind. When I started this knife (last week), I was still using a 3"x21" Harbor Freight belt sander to grind these blades. What you see here is the result of about $20 in 36 grit belts, lol. I've since ordered a Pheer 454 2x72 grinder:



After a bit more grinding:



On the bench!


Post spherodization cycles:


With its slightly shorter, slightly chubbier cousin that I forged out during the spherodizing anneal. I haven't decided whether to make the top one more of a 'heavy' chef's knife...or to use my typical gyuto geometry:


Here is the blade with my layout lines so I get my clay even from side to side. On a blade this wide and thin...the clay can do very, very nasty things to the straightness of the blade during the quench, if its not exactly, and I mean EXACTLY even side to side.


All clayed up!


So...here's where the fun starts. This blade has been heat treated no less than four times already. It's refusing to harden properly for me in the Parks 50 quench oil. Sooo, I'm going to go back to an interrupted brine quench for this blade...which is actually what I'm most accustomed to. I'm not too terribly concerned though...its always the ones that fight me most in the hardening process that give me the most spectacular hamon .

More to come as I get to it!

 

So, I thought, since this blade actually failed in heat treat...that I'd continue on with another 260mm blade I made as a replacement. I was actually able to harden it successfully this evening, so...now it's a knife .

We'll skip all the forging pictures, etc...and get to a bit before the heat treat:



Profile shots. This one has been ready for heat treat since before I built my shop. I was saving it because of issues I was having with my oil. Sure looks longer than 260mm doesn't it?? Also, the upsweep at the heel isn't really an issue, as I know the blade will curve downward in the quench, which necessitates a bit of additional profile work post heat treat. I get the basic shape in, and leave enough meat for corrections where I know it'll be necessary.

So, this is where it gets fun. I started working yesterday at 8am, with the blade in the above condition. I came in at 10pm...lol. Long, rough day...with nothing but unsuccessful heat treats. (I was working on my 255mm laser as well, so not a total loss). The blade just WOULD NOT HARDEN. Same issues I was having before I tore my old shop down. I tried three or four new ideas...all to no avail. Now...you can only attempt hardening a blade so many times before it becomes unable to be hardened on a crystalline level (did you know steel is a crystal? It also has no molecules...thus the use of 'crystalline' versus 'molecular'. Late night fact #1 there for you folks). This is fixable, but basically you have to go through the entire thermal cycle process again....which is part of what I did yesterday. This consists of heating it to 1700°F for ten minutes (it takes the oven about an hour to get up to temperature), then air cooling to a black heat (below 900°F). Then 1600°F, cool to black. After that, it's 1500°F, and quench into my Parks 50. After that I cook it for awhile in order to put it into a state that I like for grinding and eventually heat treating. The thermal cycle process takes about four hours to complete with all the ramping up of the oven, and the cooking the steel for an hour at the end. Anyhow, due to all of the failed attempts yesterday, and two more failed attempts today...the steel needed thermal cycled again. That killed four MORE hours of my day. Soooo...anyhow...in order not to bore you guys (not to mention keeping myself from looking like an idiot!), I'll just leave it at the fact that the next attempt was successful, and only the most simple thing needed changed. TWO months of work...and it was one tiny issue that was failing things, lol.

Anyhow, fast forward to now. I've got a heat treated blade, a short video, and a picture for you all . First though, I thought I'd share some of the pictures of the failures!


Yeah...that won't work.


Nope.


Uh uh.


/sigh...


This was after my 1500°F full quench. As you can see, some spots still didn't harden. That's the nature of W2 in even a fast oil like parks. You must keep the cross section very thin for it to work right.


And SUCCESS!!!


Here's a slightly better pictures...

And even better yet...a video! I stole it from my Instagram, lol.
http://vid1133.photobucket.com/albu...Knives/260mm W2 Gyuto/VID_41140130_060252.mp4

Anyhow, that's where things sit tonight. Tomorrow I'll start working on straightening the blade, and settling out the grind .

 

Fascinating Cris, thank you so much for putting this together. And I thought making a handle was tough. What do you wind up doing with all the steel that fails?

 

I'm glad to go through it with you all Myron! I love sharing my work, and I think it really makes you guys better able to appreciate the amount of care and effort that goes into them. I put 28 hours into this blade over Thursday and Friday due to the issues I was having with it not hardening properly. Now, that's not a normal occurrence, but it can certainly happen.

On the failures, unless the blade cracks...it can be reused. After a few attempts though, the grain structure has changed enough that it needs to go through the four hour thermal cycle process again before it can be properly heat treated. This one went through two thermal cycle processes. Now, if the blade continues to fail for some reason...it will eventually become too thin to survive the quench without shortening the heel to bring some thickness back to the edge. Sometimes they can be saved this way, sometimes not. This time, the blade I started with is the blade I finished with .

All in all, if I just through hardened these blades, I could sell them for a lower price point and still make more money for my pocket on each knife. But for me that's just a compromise. The beauty and function of a properly done mizu honyaki blade is just something that is a given part of the knives I make. If I won the lottery tomorrow, I'd still make the things for you guys for free, lol.

 

I got some more done on this knife last night .

First (before the pictures), I'd like to say that the most difficult part of making these is easily the initial grind. The blades are warped from heat treat, and no amount of straightening will get all the little ruffles, curves, bends, and jogs out of the edge and spine. The longer the blade, the worse the effects...and in the best case scenario you can only get the largest of them, worst case you snap the blade. All straightening has to be done at tempering heat, which for this knife is just about 400°F. Any hotter ruins the temper, any cooler and you have an even greater risk of snapping the blade. Until this last month I'd lost more blades to straightening than to cracks in the quench.

Anyhow, lets see if we can illustrate the issues that warped blades cause for setting up the initial geometry lol.


Here you see the left side. The first thing I will usually do is get a rough idea of where my blade road will sit. The knives are flat ground with spine to edge taper before heat treat. You can see here that the tip has swerved to the right, and the entire spine has moved to the right also. There is a hollow about 2" forward of the heel that joins the laid over spine to the edge. This all has to be ground out.


The right side. You can see the spine is fully in contact, as is the edge. The tip has a bit of area not in contact, but that's mostly from the first couple passes on the grinder to check for the hamon. Note also that these two pictures are after a fair amount of grinding. There were hollows in the edge on both sides of the blade that needed worked out. Edge thickness here is roughly 1.75mm, and the spine is somewhere north of 2.5mm.


Here's a composite after a good bit more work. This is all done vertically on the grinder, with no tool rest. The platen only has about 7" of usable length, and this is a bit longer than 10" of blade.



Once I've got the blade flat, straight, and the edge centered over the spine...I can start grinding in my flats. This is basically the first step to establishing the blade road. The edge is about 1.3mm here, and the spine a little under 2mm.


And after the evening's work. You can still see a little low spot right in the middle of the choil, but that will come out with the edge thinning. Right now the secondary bevel is about 2.5cm high, with the flats being roughly the same over the heel. The edge is still relatively thick at 1mm or so. The thickest point of the blade is about 1.85mm, and I don't want to thin that too very much more.

Anyhow, I'll see about another update this evening...if I can get out to the shop .

 

Way cool.... Thanks for doing this Cris.

 

very interesting WIP Cris, thanks!

 

Anytime guys! Like I said above...I'm more than happy to share!

 

So, I was out in the shop until 11:45pm last night, finishing up the majority of polishing on this blade, and working on a paring and utility knife (two knives lol). I'm more than a little pleased with this one. It has the same grind as the 'ultra' laser 'Big Ugly' (or 'Big Sexy' as some of you have named it, lol), but I sacrificed a small amount of thinness (.1-.2mm) along the shinogi and spine for added stiffness, weight, and overall feel. For myself, the ultra-thin stuff works, but I think for a general use knife it might be a bit much for some.

Measurements over the heel are:
1cm above the heel - .75mm
2cm over the heel - 1.42mm
Thickest part of the blade (2.3cm above the heel) - 1.64mm
Spine above the heel - 1.60mm

By comparison, the ultra-laser is:
1cm above the heel - .72mm
2cm over the heel - 1.38mm
Thickest part of the blade (2.45cm above the heel) - 1.53mm
Spine above the heel - .64mm (yes, zero point six four)

Both blades taper towards the tip to a small degree, and taper more aggressively from about 3" from the tip on.

Anyhow, here's some pictures:


A clean spine bevel. The crisp shinogi is important to me for food release and blade stiffness.


A hint of the hamon at 120 grit.


The choil here is perhaps 1.8mm at its thickest point.





Relieving the spine and choil. This is something I prefer to do by hand, and it can be a real chore with the way I harden my knives. But it's an important aspect of a hand crafted gyuto in my opinion. Doing it on a machine would be faster, but invites the opportunity for mistakes that would require compromise to repair, if they are repairable at all. No thanks, I'll take the extra hour to manually chamfer, round, and polish the edges.



More bevel refinement, on a 1000 grit king stone. I love the finish this stone leaves, as you can see in the next picture. It also removed material incredibly quickly. Much more quickly (and more importantly evenly) than lower grit papers. I keep the shinogi this crisp until the final grits of polishing. This maintains the designed geometry for me, and allows me to roll it over with 800-1000 grit paper later, which smooths it, but doesn't remove it.


These scratches are the bane of my existence. It can take literally an hour of polishing to remove them. Many times dropping back two or more steps in grits is the only solution. Oddly enough though, I've found the king 1000 stone a real life saver in these spots. They remove the material cleanly and evenly...and more importantly in this case, more quickly than papers.


And this is where it sat at 11:45pm last night. The polish is mostly done...I just need to smooth it out with high grit paper (to remove the streaks), then reapply the etch and rub it out a last time. From there it needs sharpened, the choil and spine final polished..and the blade will be done!

 

That is a total jawdropper, Cris. Super Freak sexy

 

Hey Cris,
I'm late to the show, as per usual. Any updates on this guy?
Really dig watching your knives come together.
One of these days...

 

Thanks you two! It should be complete before this weekend .

 

Great WIP as usual, love the hamon patterns you get on your blades:cool1

 

Uber sexy, my brother! Thanks so much for doing this. It truly is fascinating to follow along with your knife making. Did I say what a big fan I am of Mizu Honyaki?

 

So are your blades all sold during the wip or are you making these to be sold?

 

@cheflarge , you know I enjoy sharing at least as much as you enjoy watching!!

@vesteroid it depends. Some are commissions, some are sold during the WIP. A small number make it past that point though.

This one was a commission.