Question about new blades and edge brittleness

G

glwanabe

Joined
Jan 30, 2007
Messages
140
I took the Chit BAS I recieved Thursday for a workout. I cut the same brush as I did with the WWII Villager. Magnolia limbs, crape myrtle (sp) and some oak limbs and a few oak logs. I also chopped into the oak with the front of the blade. The limbs were anywhere from 1/4" up to 2".

The WWII handled it all with no sign of anything except some sap on the blade. The BAS cut well but showed signs of some chipping along the forward part of the blade, from the sweet spot forward, especially at the tip.

I looked the blade over, and noticed that when viewed from above, the left side was ground nicely convex, but the right side was flat to (almost) looking hollow ground. This is only right at the tip portion of the blade. The WWII seems to be more flat ground than convex.

I thought no problem, so I went in to steel the blade and use some sandpaper on it to get rid of the chipping. While I did get rid of the chips, it seems like the blade loses a lot of metal while sharpening. I'am using a very mild steel and some 2000 grit paper to polish the edge a little. I also stroped the blade for a good while on a nice fat piece of leather. While it got fairly sharp (dull shave) it seemed to lose the edge very fast.

Question:
1. Is it common for these edges to need to be broken in a bit with several sharpenings to get to a little harder metal?

2. Does this seem like an issue of the temper possibly being a little off? (to hard?)

The chips were not huge. Just enough that you could see breaks in the edge line. These chips happened before I had really sharpened the edge. I had passed the steel over it maybe ten times per side. I had passed the blade over the leather before this as well.

Have you had similer experiences in the past with these blades when new. I know there are many variables here. I'am outta here for the night. Please let me know what you think. The knife is great so far in every other way that I can see so far with the short time I have had it.
 
I don't know for sure but I seem to remember there is something to the notion that a few sharpenings are necessary. I am kind of surprised to hear the chipping occurred near the tip. I thought the tip was left softer and would, therefore, resist chipping.

I have thought about the fact these knives are made using a charcoal fire and a hammer and consistent hardening may not always be achieved. If that is the case, it occurs to me that etching the blades might be a good idea so one can see where the blade is hardened and where it is not.

I look forward to hearing the views of more experienced kuksters.
 
I was a little surprised as well about the tip, less so with the area further down the blade. I assume it could be fairly brittle if it is very hard. I will work the edge again when I get home from work today. I'll use the wetstone this time and see how that works out. The only thing I can see as possibly a problem is the difference in the tip area with the point grind. It may not be a big deal though, I dont plan to do a lot of stabbing stuff anyway. I was only sticking it yesterday to see about some setups for photos.I searched back through old threads and found where some owners say they feel there blades get sharper with use, because of the way these blades are heat treated intially.

As an aside, I have been reading lots of old threads. people wanting to keep that nice shiny mirror finish after working with the knife. Thats a waste of time! I really like the satin villiger finish on the WWII. Once you've sunk that blade into wood a few times the shiny mirror finish looks out of place on a working tool. Plus there are plenty of tool marks that show up anyway once they are not all blindingly shiny.
 
as mentioned, being hand made, they are all different, they are hardened and tempered by eye for color temperature and cooled using a teapot, so some variation in the temper and hardness along the blade is inevitable, it's an art to the maker. it's a tribute to their skills that they do not vary as much as might be expected with their methodoligy. same with the grind profile, maybe that day the kami was worried about something or got interrupted and didn't get the x-section as symmetrical as usual. half the joy of owning a tool is sharpening and profiling it to suit you, so enjoy. ;)

the tip is supposed to be a bit softer as it is more likely to get swung into the ground and the sweet spot harder as it's the main chopping area, but they all vary. etching as stated will show your unique temper line which can then guide your future use.
 
I've noticed side edge differences many times. I haven't experienced much problem because of it. The differences seem to be less than several years ago. Consistancy seems better. There has always been a question in my mind about this and other variences being more common with DOD than from the store site.

Sometimes the edge hardness is different after several sharpenings. I think this has been both harder, and softer. Sometimes a tiny chip does not seem to repeat. I wouldn't worry about these things, though they can be a disapointment if you're looking for a perfect blade. I've had very very few blade failures, and I'm happy to say they occured several years ago during a difficult time in HI history.

Small chips or even folds near the tip are fairly common.

munk
 
Thanks for the replies. This was the information I was looking for. I'am not looking for the perfect blade, that remains pure as Excalibur. No, I want a blade I can work with! I have worked the blade and reprofiled to compensate for the chips in the tip area. Lost maybe a 1mm, at the most. If you didn't know it had been worked you probably would not know it.

Spent some time sharpening it today and went back out to cut some with it. Still felt like the edge was breaking a bit while being steeled. Took it out and cut some small oak logs, (3" dia) and limb some branches from the magnolia tree. It cut, but took more than one swing on even some small limbs. Went back inside and worked it some more. Tried to really feel were the hard edge area was, and identified that zone, it really felt hard through that area.. Went back at it and got it pretty sharp, but not as sharp as I know it can be.

Sent Yangdu an email just to let her know what was happening. She says to send it back for replacement. I'll have to sleep on that. Hate to give up on an otherwise superb feeling knife.

I have to say that HI is a class company.




I did want to add this,

I had some down time this morning while at work. I spent a few hours searching the archives for similer situations. Like Munk and others have said it is not all that uncommon. I learned a lot by searching this topic. Steely Gunz in particular had and issue with a hard edge chipping out, as well as others just from general use on hard woods. Many people just profiled the edges and went on with there lives.

I read several post on exactly what is using this knife and what is abusing this knife. I've read a lot about etching here as well as everything I can devour about these blades and how they are manufactured. I'am no expert on forging or smithing techniqes, let me make that clear. I've read Bills write up on how he evaluated a blade, a torture test I wouldn't do to a blade just for grins.

I just wanted to add that I did search for answers and did actually find, good answers from the archives as well here.
 
I'd rather have a little chipping than rolling. If you get a tiny bit of chipping you gotta figure it is at least hard ENOUGH.

Most of the problem I have had with khuks is edge rolling (ie not hard enough)

On Granfors bruks axes I notice some chipping on the factory edge but if you sharpen it normally you don't get it again.

The only chipping khuk I ever had was an Ang Khola that lost like about 1/8" but 1" section out of the edge but I think that may have been a forging flaw rather than too brittle.:thumbup:

Lke Munk I think said sharpen the edge back a little. If it chips or rolls remember HI's are guaranteed. That is one of the VERY major advantages of HI over all other khuks. If there is some problem they will do their very best to make it right. :thumbup:
 
glwanabe;

I think I might work with it a little more. I wish I could see where on the blade you mean. Could you post a pict?


munk
 
I intend to keep working with it. I'am fairly certain it just needs to be sharpened back a little more. I really would hate to return it. It is very thick along the spine.

Munk there's not much to see right now, I've worked the small chips out. I'am going to go back and keep working it. I fairly certain there is a great blade with just a few hours work away.

I sent Yangdu and email telling her I did not want to just send it back, seems like a bit of a waste, to just give up. Thats not in my nature. Besides sharpening a knife is great therapy.:thumbup:
 
A new blade should not be behaving like this. Sounds like a heat treat issue to me. Most HI blades feel awesome in the hand, so don't fret. Let Yangdu take care of you and get a properly heat treated blade.
 
I aquired a 'return' Pen with a chip out. I sharpened it and now can't get it to chip anymore.

If it won't work send it back. See what happens.

I just re-read your post. The chipping is occuring forward of the sweet spot, expecially at the tip?

I've a chitlangi that gets little chips in that area. Nothing bad ever happened. The sweet spot is fine. I've other blades, I'm thinking of my largest AK, that rolls near the edge all the time. It's not a big deal, but I think I prefer small chips. The chipping on my Chitlangi seems to have limited out.

Now, a real hard tip, with big chips, might be a safety issue. I never had one like that. It would have to really be flying chips off to concern me.

I know a lot of folks get their edge geometry to their liking. I prefer to work the khuk down. Some blades do have a flatter side than another. I've never noticed a real problem with this. I'm no expert. I just chop a lot of wood.


munk
 
From what I've read from you all, as well as the archives, I don't think there is a problem. I'll work it out a bit, and it will probably be just fine and dandy.

An etch on the blade and sand the horn handle, should be a real user.
 
You sure we're talking about a chip up near the tip? When I've been unlucky or careless enough to drop a tip into the dirt, or inadvertently mash an edge on a rock or bit of cement, the edge certainly got a bit roughed up. But more like a series of dents (i.e. round edge indentations) than chips (i.e. sharp edged indentations).

I've seen knives chip where they've been hardened and become brittle, but I've not had that happen with a khuk ... esp. not in the areas beyond the sweet spot that are softer.
 
I've seen it, Tom. Instead of rolling, my chitlangi tip developes 'micro' chips.



munk
 
I have a 20" siru that after etching shows the hardened area "sweet spot" to start about 1" back from the tip and then extend down the blade for about six inches. The etching also showed an inclusion running parallel to the edge just about in the middle of the blade. I haven't hit anything harder than an olive tree (knock on wood) but i wouldn't be worried if i chipped it while i was working. That just means more therapeutic sharping sessions:)
 
AFAIK,the khuk's sweet spot hardness is measured at around 56 to 60 RC. But traditional method of forging wont be able to maintain the hardness standard. Wouldnt it be better if HI invest on the RC Hardware and trained the kamis at Bir Gorkha to use it, and eventually improve QC?
 
If you think that you have areas that are overly hard--DON'T STEEL THEM.

Steeling bends the edge to force it into alignment. You can do this a time or two with underhardened steel, but hard steel will crack. You are cold working the steel which will work harden it. The steeling process can crack the steel or leave it with locally brittle spots.

I sometimes steel a machete to remove a ding, but I expect that I will get a chip sooner or later in the spot that I steeled.
 
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