Eye's in blade?

K

KenH

Well-Known Member
Hello ya'll, got an interesting visual here. Take a look at this blade I'm sanding.
IMG_2647.jpg


Notice the "eyes" in the blade? I'm not at all sure what's causing that. I'm sanding with 30 wt oil and 400 grit wet/dry paper. Now, when I wipe the oil away the eyes go away.


I can not see them at all - and it's not just a reflection, I can change lighting to vary reflection and the eyes are there with sanding oil/grit, but when oil/grit wiped away I can not see eyes even with blade moved around in lighting. Now, look at other side. The eyes are still there in same place, but opposite side. Eyes go away when the oil/grit is wiped away. Ever heard/seen anything like that before?


Well, I think I might have the answer. That blade was ground using the magnetic chuck for the surface grinder. While the blade didn't seem to have any magnetic properties, the blade didn't show any attraction to iron pin, etc I suspect there were magnetic artifacts left from the magnetic chuck. I placed blade on a demagnetizer and that took care of the problem - no more eyes. The oil/steel particles simulated a ferro-fluid that is really sensitive to magnetic field.

Comments from ya'll - does my thinking make sense?

Ken H>
 
That is almost spooky! 1522028738967.png

I suspect you maybe right about the magnetic chuck. However wouldn't the knife not have been exposed to more than two magnets?

If you have a demagnetizer pass the knife thru it and see what happens! You can find instructions for a demagnetizer online, if you don't have one! Hmmmmmmmmmmmm!! 1522029023167.pngThe blade is watching you, so make it purdy!!
 
Yes, the knife was exposed to several magnets on the chuck, and they are bar magnets, not the round you see on the blade.

C Craft said:
If you have a demagnetizer pass the knife thru it and see what happens! You can find instructions for a demagnetizer online, if you don't have one!
Click to expand...

Read bottom of my post above:
I placed blade on a demagnetizer and that took care of the problem - no more eyes.
Click to expand...

That was my thinking - never seen anything like that before. I just wondered if anybody else ever had and perhaps had a better explanation.
 
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Sorry Ken, guess I did not read close enough. Bar magnets are not going to leave a round mark anyway!!!

So gonna ask another question from the pics it looked as if the spots are on the blade, at the same height on both sides! Is that so??

Ken is this a kitchen knife?? You might want to try a light vinegar etch to see if they are going to appear, after using!!

It might be something in the steel itself, perhaps from the factory so to speak!! You might want to try a light etch to see if they are going to appear, after a use.

If nothing else use it too your advantage. The miracle knife, it actually see's what you are doing!! :eek::D

Sorry I got nothing else!!! I don't know of anything that might cause it!!!! Maybe John or Ed. may have an answer but I ,........... honestly don't know!!
 
[QUOTE="C Craft, post: 361953, member: 1261

If nothing else use it too your advantage. The miracle knife, it actually see's what you are doing!! :eek::D

QUOTE]

In the absence of a satisfactory explanation this would be the obvious selling point ;);)
 
You may actually be lucky...it could have been an image of someone everybody hates, like the images people find in their French fries or a corn flake Ha ha.
 
Yes, it's a chef knife, 2" wide at heel. Best I could tell the "eyes" are exactly same place on both sides - as if they go thru the blade from side to side.

I might try etching to see what happens - I think the demagnetizing took care of the eyes and it can no longer see.

I was using a 1X1 wooden block with a strip of leather on bottom for sanding. Those "eyes" do look about right for the holes in a 1-2-3 block, but there were no 1-2-3 blocks anywhere around during work/grinding time.
 
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Ken, can I don't know were you got the steel. I have had occasion to ask a steel producer about some odd things. Sometimes they get offended but usually if they don't get a case, they will tell you! Ah................it might have been where x y & z was added.

Now days a lot of steel is made from recycled. What I am fixing to say you probably know and probably understand it better than I do.

However when they are making a run of recycled. They extract a sample and depending on what they are trying to produce they end up adding something to the steel to make it have the right make-up!
So much of x of and a dab of y and a truckload of z and you got the genetic make-up turn out right. However I have had a steel producer say well it might have been y, cause if you add to much at the end of the run, well,............ it don't always blend right!!!

OK that made my brain hurt trying to explain in layman's terms!!


You know that formula is:
Pure iron ore half a truck load
x is a bit of chromium
y is a 70 Volkswagen
z is a shot of magnesium
and steel is born! 1522203206154.png Opps shouldn't have added those ball bearings they look like eyes!!!!
 
Naw, I don't think the "eyes" had anything to do with recycled steel, scrap steel, or anything like that. It's AEB-L SS. I do think the cause was as I mentioned in first post, magnetic artifacts left over from being ground on the surface grinder using the magnetic chuck. Remember, once I demagnetized the blade the "eyes" went away.

Seeing those eyes was so amazing I just had to share with ya'll.

Ken H>
 
Ken I was more or less kidding about the recycled steel but I did remember as incident on another forum. Where a steel manufacturer commented that the reason that the steel did something (can't remember the problem) was the steel did contain some recycled steel. And what ever the problem was they had probably added to much magnesium or something like that! Like I said, (I can't remember anymore what the problem was)! To counter act what was wrong with the steel during production!! He said it was not uncommon to use some recycled steel in production these days and before the steel is poured from the crucible, they check to see if everything is in the right proportions in the run!

It is strange to me that the eyes were round and you used bar magnets if it was a magnetic thing! However if they disappeared after demagnetization that is probably the problem. It may have been something in the steel that made it migrate to that area!!

Never take me too seriously as I like to poke fun with folks, especially those I know!! See it just means I like you!! LOL
 
OK Retro, my BS meter was pegged but you still had me a lookin. I was all set to research you and this explanation! Right up to, Ok I made all of that up. LOL
 
Retroguy said:
It's a transfraction affect. During the heattreating process , high density polar atoms can reduce themselves to cylindrical elements. When quenched these elements form dyforic eyelets that appear when introduced to a salic substances like grease or oil. Ok I made all of that up.
Click to expand...


Until "I made all of that up" I was sitting here glazing over, saying, "Man, there are some smart dudes on this site. Holy crap, I have a lot to learn."
 
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