Dashi questions.

O

Omega Leather Works

Joined
Jun 13, 2007
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Hey guys.

I'm gonna make some dashi's since I could use the grind time.

My questions involve my steel. I have a few feet of 1x5/32". I know 1/8" would be better, but it's what I have. Is 1084 a good choice for a kiridashi?

Stacy recommended that I use 1095 for carving knives instead of 1084. Are there other blades that aren't well suited for making with 1084? I assume it's... Well, I'm not quite sure why 1095 would be a better choice... Stacy?

Also, I want to practice making a hamon with refractory clay. I know a dashi might look odd with a hamon (or maybe not), but again, it's just practice.

I assume it's a matter of clay coating about 1/2" or so back from the edge. Sound right? How thick should the clay be?
 
One sided? Little less than a 1/4"

1084 will be fine.

What I would do, is grind it chisel, one side going up about 1/2- 3/4 of an inch, then convex the microbevel, then put a convex microbevel on the flat side. So for 1/2" 8 degrees, 3/4" 6 degrees these are rough estimates.
 
I have a Matt Markell dashi that is close to what you describe, only differences are that the ground side is without a secondary bevel, but with a very small bevel on the back. Wouldn't quite call it micro, but it is convex. Both bevels are mirror polished and it's ridiculously sharp. One of my top three I'd guess.

I like the sound of .5 to .75" for a primary chisel grind. I've done very few zero edges though. I know it'll be delicate, but I still want to try. I think. If it sucks I could always apply secondary bevels.

It's already impossible to truly flat grind on my 1x30, so I'll have to do the final finishing by hand which I'm fine with.

Thanks for the info. 1/4" sounds really short for 25°, but I believe you. I'll just have to go more acute. I've never had an aversion to acute edges! ;)
 
Do the math brother.

http://knifedogs.com/showthread.php?7000-Flat-grind-angle-formula
http://www.bladeforums.com/forums/showthread.php/562593-Chart-of-Blade-Angles-for-Flat-Grinds
http://bimjo.com/free/widget.html
http://www.carbidedepot.com/formulas-trigright.asp

Or there's a nice little app:
https://play.google.com/store/apps/details?id=com.jacobcabantomski.app.flatgrindangle

Most of these will calculate the angle for one side of a two-sided bevel. You may have to play around with the numbers a bit to get the correct angle for a chisel grind.
 
Okay so I made an ugly little dashi last night. HT went well and it's almost ready for final finishing.

My question is...

I coated the edge with Rutland furnace cement before HT. Today while ferric chloride etching I got a darkness at the edge. I've sanded and re-etched a few times and it keeps darkening in the same spot. It's even on both sides.

Is it possible this is a hamon?

IMAG2056_zpsuovhqxdq.jpg


IMAG2057_zpsv3gl1tdq.jpg
 
Well I sanded it with 400/800 wet/dry and polished the bevel a tad. There's a pretty clear line where it darkened. Not sure if it's a hamon or not (what else could it be?), but it looks cool. I'm just surprised because I really didn't try to get one. I mean I threw some "clay" on there, but really didn't expect anything.

I'll keep playing with it to see what happens. Sorry if this is something that everyone does without problems, I just thought it would be harder to achieve?
 
Strigamort said:
Well I sanded it with 400/800 wet/dry and polished the bevel a tad. There's a pretty clear line where it darkened. Not sure if it's a hamon or not (what else could it be?), but it looks cool. I'm just surprised because I really didn't try to get one. I mean I threw some "clay" on there, but really didn't expect anything.

I'll keep playing with it to see what happens. Sorry if this is something that everyone does without problems, I just thought it would be harder to achieve?
Click to expand...

Strigamont, I hope this helps you out. https://docs.google.com/spreadsheet...RtTGdtTmdtMXNCVmVGYmRaWkE&usp=drive_web#gid=0
 
gixxer1237 said:
Did you put just a skim layer on the edge and a thicker layer towards the spine?
Click to expand...

I put a rather thick layer just where you see the line develop. I didn't put any where the dark area is. The tutorial I watched had the guy coating the entire blade, then thickening the clay toward the spine. I thought about doing that, but didn't bother since I wasn't expecting anything anyway.

Edit- oh, and I did allow the clay to cure with some indirect heat for a while. The clay turned light gray, but I very much doubt that it dried fully.

carbonsteel928 said:
Strigamont, I hope this helps you out. https://docs.google.com/spreadsheet...RtTGdtTmdtMXNCVmVGYmRaWkE&usp=drive_web#gid=0
Click to expand...

Dang I had forgotten about that calculator. Into the bookmarks it goes, thanks!
 
Did you use the 1095 or 1084? Either way you probably got atleast a temper line if not a hamon. Pretty close to the edge on the heal though. Dont have alot of sharpening left there but oh well. On a blade that thick in the body you probably need very little clay to bring out a hamon if any at all. I put a hamon on my W1 dashi I forged out. There are pics in the gallery section (redwood kiridashi) if you wanna look it up. Its just a baby hamon though.
 
quint said:
Did you use the 1095 or 1084? Either way you probably got atleast a temper line if not a hamon. Pretty close to the edge on the heal though. Dont have alot of sharpening left there but oh well. On a blade that thick in the body you probably need very little clay to bring out a hamon if any at all. I put a hamon on my W1 dashi I forged out. There are pics in the gallery section (redwood kiridashi) if you wanna look it up. Its just a baby hamon though.
Click to expand...

A temper line, that's probably all it is. I was using the terms interchangeably, but I think I meant temper line. :)

I used 1084 quenched in canola oil. I agree, the hardened portion is not very big at the heel. Honestly I made it just to practice a couple of things and it won't get much use. It was clear to me pretty quickly (like right after I cut the steel) that I made the piece too short. I still went with a tall bevel because I figured the trade off of little handle instead of obtuse edge was better for me. If it were overly obtuse there's NO way I'd ever use it for anything at all. ;)

Even so, the grind widens enough where it runs out of hardened steel that I'd have chucked the thing before sharpening into soft steel anyway.

What I practiced-

Simple flat grinding- still having trouble getting a flat grind with my shi... er... crappy platen/grinder

Simple layout- aside from cutting the steel too short it went well enough. Taper in the handle could have been done better, or not at all

1084 HT- went well as far as I can tell. Needs testing but I really like this steel a whole lot. My forge will be better soon, but for now tiny blades seem doable

Temper line- obvious

And things I've still yet to finish practicing with the knife

Ferric chloride etching- I've used the stuff many times on other knives, but I'm doing more with it on this one

Chisel grind-still working on the edge. No matter what, it should be razor sharp when I'm done

Chamfering- yet to do

Cord/resin wrapped handle- done it before, but can use the practice

Plus about a million other things that I can't put my finger on. Hell, even clamping the work down properly to drill will be a benefit in the future.
 
No, but I'm working on it. After my last post I reground it dead flat other than a couple of small areas, but for this demonstration, that doesn't matter.

There's a thread on FC that I was looking at, in it was a link to an older thread that was about how the author brought out his hamons with the acid. I loosely followed his steps. In my case sanding to 600 grit, then a 10 second dip/rubbing with a cotton pad, etc..

First thing I noticed was that the dark area reappeared instantly the second the blade hit the acid/water bath. That was fresh steel so I now have no doubt that it's a product of the clay/ht.

I took a couple of pics while doing this. I'm out of polishing compound, so just rubbed the area with green compound. There are two lines that intersect at the heel. Without diffused light it's hard to tell in the pics, but the steel is a really pretty gun-metal color. I still need to buff it out once I get some compound to see what the final look is, but I'll definitely be trying this again. Even without a temper line, hamon or ashi the steel looks good enough to try again.

The pics suck. I'll try to post better ones after I get more polishing compound.

IMAG2066_zpsaxtbsf0d.jpg


The instant it hit acid

IMAG2060_zpsmftlbh9f.jpg


After light buffing

IMAG2064_zpsrgaue1xf.jpg
 
Last edited:
Bah! Now I'm confused. I polished the bevel to a near mirror and the line is gone again.

IMAG2079_zpsiidptiyk.jpg


Unless someone else has a better idea I think I'm gonna forget about FC for now and try rubbing with a super diluted lemon juice.
 
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