Critique please - first few knives - 3v, Tsukamaki, integral, stress points

K

kwakn

Joined
Oct 17, 2009
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I posted these pictures in another thread but didn't specifically ask for a critique and subsequently didn't get any. Y'all are either way too polite or I need to stop hangin' around 0hedge. I humbly seek your help to make these better.

Experience:
I've ground 6 blades (after practicing on a half dozen wood and scrap steel), have a 48" Coote, a vice, files and 20 sq ft of shop space...in the corner of my garage...next to the fridge... a temptingly bad combination for sure.

If I should edit to one topic, please advise.

I do feel the need to repeat myself from the other thread but again, thanks to all of you who've offered advice and guided me along the way. This all started with me starin’ at piece of plate sayin’ ‘now what’!

So…

1. My biggest concern is the integral bolster/habaki transition to the blade and potential points of weakness. My goal was to have the look of handle-guard-habaki-blade. My impressionist rendition was butt-handle-turkshead-integral bolster-blade. I didn’t want there to be an additional plunge line per se but I don't want the blade to snap from a weak point. To my limited knowledge, this is relative to several variables given the steel type CPM3v: normalization before hardening, overall hardness, geometry… any others? (I used Peters and they follow the recipe and get to 60HRC) so what are the tradeoffs? How 'far' can I expect to push the geometry envelope and retain artistic impression? A slight radius at the transition of habaki to blade? Ok - How big does that radius NEED to be. I would prefer it to be as small as possible but not sure how to quantify it.
2. How do you ensure the moisture barrier at the turkshead and butt areas? (Make sure it's soaked with epoxy?) They are, but I don't have enough experience to know if there is truly a moisture barrier at those two points after epoxy has been applied.
3. If you see other design flaws that could improve performance please do point them out.
4. Stacy – if you read this, would it be asking too much to categorize these designs? I hear it may be presumptuous to call them tantos. Maybe picotanto or pockatana as suggested by another forumite.

1st 6 pics are:
Steel - CPM3V to 400 grit - Peters HT to a requested 60 rockwell.
OAL - ~8.5"
Goal = Flat grind - that turned into a slight convex grind :o
Blade Length - 3.875"
Width - .8125” - spine to edge
Thick - .1875” at it thickest, slight taper toward the point.
Wt: 5oz, the other 5.5oz

Integral bolster and butt all from 1/4" stock


Epoxy resin (ESP155 marine/several simultaneous applications) was painted onto .25" nylon lace wrap, handle is backed with leather and heavy nylon waxed thread (same as used for the turkshead) to bulk up the handle before laminating with stingray.

Weight was reduced in the handle during the waterjet process (outsourced) by including a series of holes and then thinning the handle (files and grinding) to .1875” as well, leaving a .25" butt and bolster.


The knives haven't been sharpened yet. There are little scratches near the edge that I believe will come out in the convex edge sharpening phase.

The last 5 pictures are WIP. They show the thinning and shaping of the handle (that were done to the smaller knives as well) ready to accept leather and cord.


Their dimensions:
OAL - 9.75"
Width – spine to edge - 1"
Blade Length - ~4.625”
Thickness - .375” to .4375” - again from .25" CPM3V but the bolster/habaki is the same on all of them.
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Your design and execution are both pretty spotless, IMO. As to questions 1 and 2, I think testing is in order. Your notch above the 'habaki' really does look like it could be a stress riser, but it's a really easy thing to test — make one with and one without it and see how easy and where each one snaps. From what I understand about 3v, even if the notch does increase breakability, it may still outperform other knives in its class in this area. You'll also want to ask yourself some questions about the intended use for these knives (unless you already have. If so, I'm curious.), and whether tensile strength is particularly important for the design.
The same goes for the moisture barrier issue. You could even use the broken pieces from your other tests for this. I would soak the entire handle in vinegar for a couple of days, and then take it apart and see what got etched. If you're only painting the epoxy on, you may not be getting the level of penetration you need. From what I understand, Rich Marchand, who also does leather-backed, cord-wrapped handles, soaks the handle in epoxy for some period of time.
For your final point, I say call it whatever you want. There's lots of makers calling all kinds of things tantos with complete disregard for what a tanto originally was. If you want to go with picotanto or femtokatana, that's fine, too. What we call our knives is important (IMO), but probably the least important thing about them.

- Chris

ETA: I want to elaborate a little bit more on your final point. I admit that my comments here are unsolicited since I'm not Stacy, but here it is anyway.
Since I mentioned Rick's knives a little bit ago, I'll start out by talking about his knives. He has a knife listed as "Tanto w/ Guard" (http://wildertools.net/?portfolio=tanto-070111). This knife certainly evokes a tanto (as do yours), but it is not a tanto in the strictest sense. Neither is his "puukko" a puukko in the strictest sense (http://wildertools.net/?portfolio=puukko-s-curve), nor his "guppy" a fish (http://wildertools.net/?portfolio=guppy-052610). I've never heard anybody complain about these names and if I did, I wouldn't listen.
Suzuki makes a sport bike called "katana" that in no way resembles a katana nor is even a sword/knife. Do a google image search for "tanto" and you'll see lots of knives called "tantos" that range from traditional tantos to knives that only barely evoke one in the slightest.
 
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Chris, Thanks. Not sure how to break out all your points and reply to them. Yours are in italics.
Hesparus said:
As to questions 1 and 2, I think testing is in order. Your notch above the 'habaki' really does look like it could be a stress riser,
The notch was a one time unique fix, er feature. I still have the integral transition to the blade which IS design intent. That's a bigger concern.

From what I understand about 3v, even if the notch does increase breakability, it may still outperform other knives in its class in this area.
That had entered my mind. It IS relative to the perfomance of others. Obviously two knives of 3v are easy to compare. It is the comparison to other steel types where 3v may have a structural advantage and permit some bending of traditional design 'rules'. Is there an elasticity measurement? Maybe before I go breaking things, I'll try to do some more research.

You'll also want to ask yourself some questions about the intended use for these knives (unless you already have. If so, I'm curious.), and whether tensile strength is particularly important for the design.
I have. It is a general all around knife... for me that is. Gut a fish, make kindling (batoning), slice a piece of meat, cut rope, break down cardboard boxes. Knowing 3V, it will do this and more. Tensile strength isn't important to me but it may be to someone, so I think I should learn about it for this particular geometry and steel.

The same goes for the moisture barrier issue. You could even use the broken pieces from your other tests for this. I would soak the entire handle in vinegar for a couple of days, and then take it apart and see what got etched. If you're only painting the epoxy on, you may not be getting the level of penetration you need.
Good idea. I have some ways to test this without destroying anything.

For your final point, I say call it whatever you want.
Thanks. My goal was to take the look of a katana and scale it down to my skill and ability. I have no problem calling it a kaiken, kwaiken, tanto, or whatever. Right now I'm leaning toward pocketana:)

Ed
Click to expand...
 
OK, I'll give it a shot:

First, they look good. The tsuka-maki is very nice looking. The turk's head is a good feature. Milling and finish is very nice.

Those should be real rugged beasts. 1/4" is thick for such a small blade. I wouldn't worry about them breaking.

The handle looks a bit fat for the blade size. It could be the photos, but perhaps a smaller handle would be more balanced. Remember that with a wrapped handle, you need to reduce the tang width by the thickness that the tsuka-maki will add.

The design and shape are, as Hesparus said, not really a tanto. If you wanted to call it that type of blade, it would be an aikuchi anyway, since it has no guard. They are really too short for that style, and the best name would be "Kaiken" ( also spelled Kwaiken), which means pocket knife. It was often hidden in a sleeve or pocket. They have plain handles and sheaths.
 
Something else to think about: I don't think this style of cord wrap is conducive to some of the tasks you have in mind for it. If you're gutting fish and cutting meat, you're going to get guts and blood and things on the handle. This style of handle leaves lots and lots of little crevasses for bacteria and junk to get stuck in, and which cannot be cleaned easily or thoroughly (you'd have to boil or autoclave it, which would break down the epoxy). This would not have been as big a problem on the japanese originals because those were designed (1) to have removable handles and (2) to be rewrapped when necessary. An epoxy-soaked handle cannot be removed without completely redoing the handle.
Also, to add a layer of subtlety to the naming issue, if you consider the turk's head to be a small guard rather than a fuchi, you could get away with calling your knife a hamidachi.

- Chris
 
Thanks gents.

Stacy - Rugged was a goal. I've been nudged to go thinner and probably will. The tang is thinned to 5/32nds and then I experimented with different backing layers to achieve a thickness in the handle that felt good with and without gloves. The smaller ones with handles on already are gifts for my brothers. They both have fairly large hands so we did some blind tests for feel. Any thicker and it WOULD look out of proportion for sure. Here again, tradeoffs.

Hesparus - The blood and guts on the handle is a concern since they aren't dipped. I was afraid of getting too much epoxy on them and didn't want them to turn out shiny and lose some of the detail. Might have to take fish gutting off the list. That's ok. I WILL test to find out how water proof they are though. Some clean up from tree sap and dirt will be necessary and they have to be able to be maintained. They are meant to be users.
 
I use system 3 epoxy impregnate on my cord wrapped handles . Once cured they are 100% water proof and can be cleaned easily with soap and water, I often use windex and wipe down with a cotton towel. I also will give it a good going over with compressed air to clean out all the nooks and crannies.
When you apply the epoxy drenge it and lay it on until it is soaked, fill in any and all crevices, gaps and spaces. Turn the knife in all directions so the epoxy will flow everywhere in the handle and hang it up. Let is soak in for a few minutes. Then as Mike Snody demonstrated in his video. Take a cotton towel and give the handle a pat down to remove all the excess epoxy. I then go over it second time and repeat. Once you pat it down with a cotton cloth the grip will come out looking and drying perfect and it will be a totally sealed unit.

It is very easy to maintain with soap and water and patting or blowing dry. I use mine all the time cleaning fish and using in the camp with food. The best part is this style of grip is non slip and no matter how gooy things get your grip is secure.

This is what it ends up looking like treated like I described
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Adam. Thanks. I'll make sure I load 'er down. I thought I did but it kept absorbing more and more. When it looked like it wouldn't take any more I stopped. As suggested, it was wiped down with a cotton rag to eliminate any shinyness. I did not however, turn the knife to make sure everything 'flowed'. Good tip! The outer surface still has some texture to it, especially the turkshead so I know 'stuff' can get in there. Just not enough experience to know if it's just on the surface or not.
 
Kwakn,

Once you get it all soaked up do be afraid to let it sit and soak. The epoxy I use takes about 18 hours to dry, so a few minutes of soaking and filling in all the nooks and crannies is just fine. On a handle like the one I showed it actually takes about .75 oz of epoxy by the time I am done :)

Oh and I find wiping and brushing not good for some cord. It can smudge the cord and make it look fuzzy. I squeeze and dab to remove excess epoxy and the cord comes out looking natural.
 
Very nice execution!

I agree with the comments about the handle seeming a little big for the blade in the picture. How do they feel in person?

In this nice of a knife, the polished, shiny tip looks out of place to me versus the matte blade - is it like that in real life, or is that an artifact of the photo?

These are really good - keep at it!
 
Tait said:
Very nice execution!

I agree with the comments about the handle seeming a little big for the blade in the picture. How do they feel in person?

In this nice of a knife, the polished, shiny tip looks out of place to me versus the matte blade - is it like that in real life, or is that an artifact of the photo?

These are really good - keep at it!
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Tait, These are gifts for my brothers with somewhat larger mitts, we live in the northeast, these were built to be used, and we're outdoor people regardless of weather. So to get the proportions in the handle, I pulled out a boning knife from the kitchen drawer, my Buck 112 (as reference points) and then made two different mock-ups of the knife in question. One mock-up had a thinner handle by 5/32nds. While the aesthetics of the thinner handle was more pleasing, it lacked 'feel'. It was fine in a bare hand but got a little 'lost' when handled with a gloved hand. The production knives all had aesthetically large handle proportions for small or thin blades. The extra 5/32nds filled the hand when wearing a glove and was still comfortable without gloves but DID detract slightly in the 'looks' category. It was a trade-off but an intentional one with the ultimate owners input.

That last picture in the series to which you refer is still a WIP. It's back from HT and I'm putzin' with the final look. I'm trying to accentuate the tip. If it was hollow ground, the delineation would be obvious. I haven't decided to keep it or take some 400 grit to it. I also got my first pint of ferric chloride and started experimenting. I may end up etching. Don't know yet.

Very much appreciate you taking time to comment. Thanks. I'm very much a rookie at this and welcome the feedback.
 
As a beginner myself, I have to say you clearly have skill, and it sounds like you are making the big decisions for the right reasons.

Thanks for sharing the decision making process.
 
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