Question on katana dents

[Ken-Hawaii]

I have a zinc-beryllium iaito that I had made in Tokyo about 10 years ago that gets swung for 5-6 hours each week in MJER & Shinto-Ryu. On the left side of the mune (while holding the katana), there are hundreds of tiny dents going the entire length of the blade. There are no dents at all on the right side of the mune. I'm right-handed, my saya is made of the usual ho wood, & there is nothing but wood at the koiguchi. I don't really notice the dents when doing noto, but am starting to wonder if they might cause eventual blade failure.

I've been a professional engineer for 40+ years, & have worked with metals for most of that time, but I'm absolutely stumped. One other student in our dojo has a few dents on his mune, but nothing like mine.

Any ideas???

[pgsmith]

Hey Ken,
Could it be flaws in the copper or chrome plating? As long as the plating is not actually flaking off, it should be fine as long as it doesn't bother your practice.

[Ken-Hawaii]

Paul, as far as I can tell, there isn't any difference in the plating in & around the dents. I know there's some question on whether zinc-beryllium blades are plated at all, but in any case, the dents are far deeper (1/16 inches) than could be accounted for by plating problems. And of course with dents only on one side of the mune, plating problems wouldn't make much sense....

I'm not yet panicked about the blade breaking, although our Sensei's last iaito did fail catastrophically a few months ago, & I had to (literally) jump over the piece that went skittering across the dojo floor towards me. I just can't imagine what would be causing the dents in the first place!

[DDATFUS]

I just can't imagine what would be causing the dents in the first place!

Do you have a significant other with a wicked sense of humor?

[Ken-Hawaii]

Ha, ha....

We actually had our iaitos built at the same time & place, David, & although she doesn't swing hers quite as much as I do mine, there's no sign of dents on her blade.

Truly strange.

[pgsmith]

That is truly strange. I don't think I've ever had an iaito develop dents in it.

For what it's worth, my beryllium iaito (from Nosyudo) has copper, then chrome plating on it. Found that out after I managed to stick my kissaki into a wooden wall support at home (no more practicing in the house for me!). It badly bent the end of the kissaki and I had to file it down to repair it. :)

[Lance Gatling]

I have a zinc-beryllium iaito that I had made in Tokyo about 10 years ago that gets swung for 5-6 hours each week in MJER & Shinto-Ryu. On the left side of the mune (while holding the katana), there are hundreds of tiny dents going the entire length of the blade. There are no dents at all on the right side of the mune. I'm right-handed, my saya is made of the usual ho wood, & there is nothing but wood at the koiguchi. I don't really notice the dents when doing noto, but am starting to wonder if they might cause eventual blade failure.

I've been a professional engineer for 40+ years, & have worked with metals for most of that time, but I'm absolutely stumped. One other student in our dojo has a few dents on his mune, but nothing like mine.

Any ideas???
As a professional engineer, I reckon you have two choices:

1. Recognize that the gremlins or another supernatural force have induced tiny dents in your iaito.

Or... ruling out magic and the fey....

2. Ask you kids or who else (including you) who has access about it. :D

Lance

[Ken-Hawaii]

Here in Hawaii, they call gremlins "menehune," Lance, & they're supposed to only do good deeds :rolleyes:.

Our kids are grown & long gone, & one grandkid swings her own sword, so I kinda' doubt that she'd sit there with a tiny hammer & make dents in mine. I've been trying to take a digital photo that shows the dents, but so far I haven't been successful.

I've also been using a 20X magnifier in bright sunlight trying to find any sign of copper, or even plating, in my iaito, but again no luck. Just looks like plain old metal with no bubbles or imperfections, other than the dents. If I could just figure out why they're only on one side of the mune, I'd be a lot happier!

Well, as long as I can keep swinging it, I guess a few (hundred) dents are't going to make much difference :D. Thanks for the comments.

[Chidokan]

what are you cleaning it with, perhaps some reaction with the chrome??? I have seen some pitting before on chrome like this, and it is possible you always leave it with one side down... be good if you put it under a scope and took a look to see if it is corrosion or dents.

Or is it you have spiky hair and a bad chiburi????:laugh::laugh::laugh:

[Ken-Hawaii]

My, aren't we hilarious today...? :shot:

Nope, just plain, old choji oil on a soft piece of toweling, Tim, same as I've been using for 20+ years. And with dents, rather than pits or corrosion, as seen under my 20X loupe, I'm still in the dark. If they weren't just on one side of the mune, I'd probably drop the whole thing. I generally keep the iaito in the saya, edge up, although if I'm going to train the next day, I do tend to leave them in my waterproof case, either standing on end or lying down.

Oh, yeah, if my chiburui was that bad, I'd likely have scalped myself by now, as I train with shinken in Shinto-Ryu :p !!

[Bruce Mitchell]

I know it is a long shot, but have you tried peering into the saya aided by a small flashlight? Could you be knocking the edge of your koiguchi when doing noto? I'm just throwing out guesses here, since it is an intriguing mystery!

[Chidokan]

I guess its possible you have something hard bouncing around in the saya, maybe a metal chip, or a bit of grit??? Give it a good tap onto a white piece of paper and see what comes out.. just a thought, but the chrome isnt bubbling up due to something going on underneath by any chance, and you are taking the top off?

in the meantime, avoid spiky hair...:D

[DDATFUS]

Hey, guys, I just realized that this thread has been on e-budo for DAYS without a single person saying "Ask your sensei!" :eek:

That must be a record!

[pgsmith]

That must be a record!
Nah, it's just that we know Ken has been around long enough to know the more obvious answers. Now we're trying to come up with really obscure answers ... like spiky hairdos! :)

[Tripitaka of AA]

Could it be related to the technique shown in this illustration? :) Always popular with pirates, IIRC.

[Ken-Hawaii]

It was a good idea to look down the saya with a flashlight, but I couldn't see anything except the ho wood. And when I tapped the saya onto some paper, nothing at all came out except some cat hair (not tremendously unusual as my wife has eight very hairy Maine Coon cats). Hmm...would you call it a dust bunny or dust kitty...:confused:? And as my koiguchi is wood, I can't see how that would dent the metal mune, especially on one side.

Tim, I'm really trying to find any sign that the chrome is bubbling or something similar, but I'm just not seeing that. No sign of chrome plating at all, really. I'd love to find out exactly how they manufacture zinc-beryllium blades, BTW. From a metallurgy standpoint, it's not a very hard alloy - which is why they can't be sharpened - but I haven't been able to find any info on how shiny it is without plating.

Oh, & I did ask Maeda-Sensei about my iaito, who had no ideas at all.

Okay, since I have a 13-foot tsunami bearing down on me out here in Hawaii, I think I'll focus my energies on how to re-anchor my boat :eek::eek:!

[Bruce Mitchell]

It was a good idea to look down the saya with a flashlight, but I couldn't see anything except the ho wood. I had been thinking maybe there was a hard knot or an inclusion in the wood of the saya that might have come to the surface with wear. The good news is that we are eliminating potential problems as the diagnosis progresses.

And as my koiguchi is wood, I can't see how that would dent the metal mune, especially on one side.
I was thinking that some saya have a metal band that reinforces the koiguichi, or sometimes horn or hard wood (I've also seen plastic). My thoughts were that if this material was harder or as hard the surface of the iaito it might account for dents. If you are fairly consistent in how you bring your sword to the koiguchi to do noto it is plausible that you might always strike the same side of the mune (long shot guess here).

Okay, here goes another shot in the dark. Do you were a reinforced knee brace on your right knee? If so you could be knocking the edge of the mune when doing the first part of the noto during Ukenagashi (when you place the back of the blade against the right thigh above the knee).

Or, maybe some of those crazy cement eating termites you have on the islands have been gnawing on it?

[Ken-Hawaii]

Metal-eating termites?? That's almost as scary as thinking about cats with hands :eek:!!!

I mentioned in passing that my wife & I both had our iaito made at the same time & place, & that we both train in MJER. Her iaito has none of the same problems that I'm seeing. And, no, she's not more gentle than I am!

Strange.

Awaiting the wave... 15 minutes away.... The water supply has been turned off on all islands; how long can you subsist on :beer:?

[Lance Gatling]

I have a zinc-beryllium iaito that I had made in Tokyo about 10 years ago that gets swung for 5-6 hours each week in MJER & Shinto-Ryu. On the left side of the mune (while holding the katana), there are hundreds of tiny dents going the entire length of the blade. There are no dents at all on the right side of the mune. I'm right-handed, my saya is made of the usual ho wood, & there is nothing but wood at the koiguchi. I don't really notice the dents when doing noto, but am starting to wonder if they might cause eventual blade failure.

I've been a professional engineer for 40+ years, & have worked with metals for most of that time, but I'm absolutely stumped. One other student in our dojo has a few dents on his mune, but nothing like mine.

Any ideas???
You didn't say - where they there when you bought it, and simply didn't notice them?

Or, not metal-eating termites, but those critters from The Day the Earth Stood Still. They're just chilling out because they're in Hawaii.

[Lance Gatling]

Also, are you sure that's zinc-beryllium? Beryllium is nasty stuff, its dust is toxic. I work in the aerospace business, dealing with it is a necessary pain.

AFAIK most iaito blades are brass, zinc, aluminum alloys of some sort.

[Chidokan]

cat hairs???
http://www.dontstayin.com/chat/c-4/k-1350456

[Brian Owens]

Also, are you sure that's zinc-beryllium? ...AFAIK most iaito blades are brass, zinc, aluminum alloys of some sort.

You said it yourself; most iaito are zinc-aluminum alloys. Zinc-beryllium iaito do exist. (Possibly they are zinc-aluminum-beryllium or some other combination.)

Adding beryllium is said to increase the stiffness of the blade, at only a small cost in increased brittleness.

[Brian Owens]

...Or, not metal-eating termites, but those critters from The Day the Earth Stood Still.

That movie was an abomination!

This is the only true TDTESS: http://www.imdb.com/title/tt0043456/ ;)

http://upload.wikimedia.org/wikipedia/en/3/3f/Day_the_Earth_Stood_Still_1951.jpg

[Ken-Hawaii]

My wife & I think your attack cats are hilarious, Tim! Thanks for a good laugh. But I'm not showing it to our clather of cats, either :nono:!

I certainly would have noticed any dents when I had my iaito made, Lance; it was my first custom blade! But I don't have any idea when they showed up, either. I was watching an old Musashi rerun a few weeks ago & was giving the iaito a full cleaning (tsuka removal, etc.), when my fingers noticed the line of dents. I had Linda check her blade, but no dents on hers. I suppose they could have been there for quite awhile. The dents aren't at all noticeable when I do noto, but that could be because Sensei has been working on Okuden with us sempai for the past six months, & there's not much mune that hits my hand.

When I had our blades made, I checked at length to find the best materials, & zinc-beryllium was at the top of the list. I wasn't aware that the beryllium increased the stiffness, though, so thanks for that tidbit, Brian. I know about its toxicity, Lance, but that doesn't matter once it's alloyed, thank goodness, metal-eating critters notwithstanding :D:.

[Chidokan]

I think I NEED a photo now, you have piqued my interest...:D

Does it look like chatter marks then?

[Lance Gatling]

Metal-eating termites?? That's almost as scary as thinking about cats with hands :eek:!!!
...........
Awaiting the wave... 15 minutes away.... The water supply has been turned off on all islands; how long can you subsist on :beer:?
So, how was the tidal wave? Water still off?


"

On the subject of iaito, there are a lot of opinions, & here's another from a chemical engineer. The two primary types of "true" iaito are made from either a zinc/aluminum or zinc/beryllium alloy. There are advantages to each of these, primarily for density (weight) & balance; & of course neither can be sharpened. It's bloody hard to stick chromium chemically to either of these alloys, so as several iaito manufacturers have explained to me, they "direct anodize" that nice shiny surface, but it's not chrome because it doesn't have any chromium in it. I can figure a couple of ways to actually chrome an Al-Zn surface, but it would take several intermediate metals (nickel & either steel or gold), which would drive the iaito prices even higher than they are now. I stick with Zn-Al primarily because I happen to know that beryllium is one of the most poisonous metals we're likely to encounter; check out www.webmd.com/hw/health_guide_atoz/nord481.asp if you want to get scared.

"
That makes more sense... ;)

[Ken-Hawaii]

They turned the water back on after about eight hours, but as I haven't run out of beer yet, I don't much care :p. We had about a four-foot surge in Kaneohe Bay, & my boat looked rather strained, but no damage in our neighborhood, thank goodness.

So you're another ChE, Lance? I took a dual major in that & petroleum engineering, & so of course haven't been doing much of either for the past 30 years.... I used to design & build nuclear reactors, & we used beryllium tools to prevent sparks, so I'm akamai about its toxicity (new Hawaiian word for ya').

Tim, chatter marks are a good way to describe the dents. They start about 2-1/2 inches in from the munemachi & wander down one side of the mune to about 3 inches before the boshi. I've been trying to take a good photo of the area for about a week, but haven't succeeded as yet; to see the dents, the amount of light I need to use causes 'way too much glare. Even Photoshop hasn't helped, but I'll keep on trying. I want to send a photo back to the manufacturer to see what they have to say, & of course will post it.

[Brian Owens]

...I've been trying to take a good photo of the area for about a week, but haven't succeeded as yet; to see the dents, the amount of light I need to use causes 'way too much glare. Even Photoshop hasn't helped, but I'll keep on trying. I want to send a photo back to the manufacturer to see what they have to say, & of course will post it.

To reduce glare, change the angle of the light; angle of incidence equals angle of reflection.

Also, the larger the light source the better, all else being equal. A soft box would help, or shooting outdoors on an overcast day or in the open shade on the north side of a building.

A tripod is almost a must have for sharp images at the low shutter speeds you'll need in dim conditions, since you'll want a moderate or small aperture for sharpest focus.

HTH.

[Ken-Hawaii]

Brian, I've been a professional photographer since about 1970, & have pro-level gear, but still haven't been able to capture the damn dents clearly. I've tried a soft-lightbox, but then I don't get the specular highlights on the dents. I've played with depth-of-field, of course, along with a small spotlight, reflectors, & a dozen other things....

It's a lot easier to shoot Nihonto :(!

[Brian Owens]

...I've tried a soft-lightbox, but then I don't get the specular highlights on the dents.

You may have tried this, but just in case...

Aim the soft box quite a bit downward, and set the stand so low that the "ceiling" of the box is just barely above the level of the blade. You'll be feathering the light to skim across the blade. (A strip box works even better than a square- or octa-box.) If you have grids for your box, use one.

Mount the camera just above the box, with the lens axis not quite parallel to the light-to-blade axis.

You won't have specular highlights, but you should get strong shadows in the "bowls" of the dents that will reveal their depth and contours.

[Chidokan]

alternative analysis...

Inputs - Hawaii, hula girls, beer, tidal wave, iaidoka, boat.

output - drunk iaidoka on boat getting knocked around by hula girls' hips during nukitsuke due to her losing her balance due to tidal wave...

final result - headache and chatter marks in blade...also nagging wife who wants to know why a girl was on your boat...:D

[Bruce Mitchell]

I was thinking, for the purposes of taking photos, can't you apply something either to the dents or the surrounding surface to make them stand out? I'm thinking that if you rubbed a crayon across the surface of the mune you might be able to highlight the dents without having to get all fancy with shadows.

[Ken-Hawaii]

alternative analysis...

Inputs - Hawaii, hula girls, beer, tidal wave, iaidoka, boat.

output - drunk iaidoka on boat getting knocked around by hula girls' hips during nukitsuke due to her losing her balance due to tidal wave...

final result - headache and chatter marks in blade...also nagging wife who wants to know why a girl was on your boat...

:D:laugh::D:laugh: Best laugh we've had all weekend, Tim!! Mahalo!!

Not a bad idea, Bruce. Now all I have to do is persuade one of my grandkids to loan me a crayon.... I don't seem to keep them around any more.

Tried your light-box idea, Brian, but can't really pick up the shadows that way. Did find out that it's fairly easy to go cross-eyed after about 15 minutes; Linda offered to take a photo of my :rolleyes:, but I decided to focus on a :beer: instead.

I was going to bring the iaito to our local sword society meeting, but got rained out this morning in jodo to the extent that a hot shower was vastly preferable to an air-conditioned room. Probably don't let drowned rats into the building, anyway....

[Brian Owens]

...Tried your light-box idea, Brian, but can't really pick up the shadows that way.

Hmm, skim lighting is a standard technique for showing small surface details: orange peels, weathered skin, etc.

Just to be sure we're on the same page; I said a soft box, not a light box/light tent. Was that what you were using?

Soft box:

http://www.profoto.com/content/2/8/5/2/fecbfa88/softbox2X3.jpg

Light tent:

http://ep.yimg.com/ca/I/yhst-67636109930145_2094_23679424

Light tents are no good for bringing out crisp shadow detail; they're intended for just the opposite.

The best soft box for this purpose would be a somewhat specialized version called a striplight:

http://www.profoto.com/content/2/8/4/0/a625f892/softbox1X6.jpg

[Ken-Hawaii]

Sorry for the delay in responding, Brian - had to fly back to the mainland to help out a very ill family member. Couldn't even bring my iaito to train :(.

Okay, I see what you're showing me for the softbox, & that isn't what I have. My setup is more like a tent with diffused light throughout; couldn't figure out how to get specular highlights with that rig. I also have a lightbox that I used to use to view slides; haven't tried that as yet. Could that serve as the strip light you described?

[Brian Owens]

...I see what you're showing me for the softbox, & that isn't what I have. My setup is more like a tent with diffused light throughout; couldn't figure out how to get specular highlights with that rig.

Yeah, that wouldn't work at all; those are designed NOT to make shadows.


...I also have a lightbox that I used to use to view slides; haven't tried that as yet. Could that serve as the strip light you described?

Maybe. You could use some black paper to cover most of it, and just have a thin but wide strip of light coming out from it.

If you have a tripod, so that you can get sharp long exposures, you don't need a really bright light like a strobe. That being the case, you might find any manner of long, thin lights would work: flourescent tubes, automotive work lights, etc. The key is to have the light skimming across the blade.

There used to be a good Web page on sword photography, but I can't find it. If I run across it again I'll post a link to it.

[BJohnson]

There used to be a good Web page on sword photography, but I can't find it. If I run across it again I'll post a link to it.

I found this, http://www.arscives.com/bladesign/swordphotography.htm
which has lots of information on composition but not so much on lighting. It was the only page I found through the first 50 or so search results on Google that wasn't a stock photo site.

-Beth

[Brian Owens]

I found this, http://www.arscives.com/bladesign/swordphotography.htm
which has lots of information on composition but not so much on lighting.

Yeah, I found that one and many others that weren't the one I was looking for. The one I'm thinking of showed his setups using a glass bench to set the blade on, black backdrops, the light and camera positions, use of polarizers, etc. It was on technical photography, rather than on decorative or "art" photography.

Maybe this summer, when I have more free time, I'll do my own blog on the subject.