Damaged edge under magnification

Gator97

Gator97

Joined
Apr 10, 2000
Messages
3,794
Nail Impact damage.

I was chopping up the old frame that used to be housing lights in my kitchen.
First contact with the screw was unintentional. But, once I realized the edge needed major sharpening I went on. In the end I ended up with really messed up edge on my HI GRS.
Well, since it happened. Good chance to test new macro photo setup, including new, more powerful lense and flash. I think overall results are better than prev photos. Although I still have to take a plunge and get better copystand :( Whtever I have can't hold heavy equipment steady enough... At those magnifications if you even breethe in wrong direction vibration is visible on the pix...

Here's macro photos of the demaged edge. Damage type nails/screws.
As for the pix. Magnification is either 24x or 40x, I figure you can tell by the level of detalization.


Same section, different views.

Next, first pic is 24x of damaged section. Next 4 pix show 40x magnification of vdifferent subareas.
 
Next major section




And the last one, large dent caused by yet another nail @ 24x and center of it @ 40x



I'll post normal view later, obviously I forgot to take normal pic with all this mess.
 
I'd like to see the normal view of the edge. These macro pictures made me cringe. The visual equivalent of nails on a chalkboard. Ouch.
 
Ack, i am going to have nightmares now after seeing them close up's.

Nice free hand macro work though friend.

Makes ya think about the cutting edge a bit more after seeing them doesnt it?

WR
 
Nice shots, little damage considering the impacts, I would like to see less fracturing though. There are some clear cases of brittle failure and ideally it would be more plastic.

-Cliff
 
I suppose that the brittle fracture is due to the edge hardening method employed by the kamis. They pour water on the edge to get a hard edge on a soft body. The 5160 would normally be an oil hardening alloy so this is a pretty quick quench on the edge. I don't think they go through a tempering step either. There is no way you will crack the blade as a whole, but the edge is certainly likely to be brittle. It is well supported by the convex grind and the soft, but rigid blade body so you probably only see these problems when chopping steel or rocks.

PS. This is my 4,000th Bladeforums posting. The counter keeps rolling on so the only way I can track myself is to leave an occasional bread crumb like this.
 
Interesting. I'll post more "general" view of the damaged portion, but after all that ordeal I never got impression that the dege was brittle. I think it's hard to judge from 40x magnifications, but may be I am wrong.
Anyway, I'll post normal views tonight.

BTW, which pix show brittle failure? Also, bear in mind all that is not from the single impact, like I stated above only first contact was accidental, after that I knew there were nails and scres, just chopped through them. Total I was chopping around 35-40 mins and as far as I remember it was either 14 or 16 nails/screws in the frame I had to deal with.
 
Here's more general view. Should be relatively close to real size.



Donno about others but to me it's quite difficult to relate macro pix to this view :) Nevertheless those above come from this poor fella.
I should be getting new copystand this week or next. Should help with vibrations and I can take more interesting pix.
 
How thick is the blade behind the damage? in regards to the more of failure, to be clear, I think the blade did better than most, certainly the current crop of stainless tacticals, however I think you can get more plastic deformation in that class of steel, some of the shots show very peaked cracks which apex to sharp points, and form impacts into nails and such you can get more rounded folds. Interesting contast of picture sizes, the highly magnified ones don't indicate much to me in terms of durability mainly as I have nothing to benchmark it against visually so you can't judge if it is bad or good, the regular shots though seem to indicate too much damage, but if the edge is very thin it is to be expected.

-Cliff
 
I'll measure the edge thickness tonight. Now I am curious about comparisons.
On the weekend I'll chop the same screws (still have them) with Beater CRK Project II. We'll see how that will fare and then we can compare.
 
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