Can someone please tell me what I'm looking at ?

S.Grosvenor

S.Grosvenor

Fulltime KnifeMaker
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Jan 24, 2010
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Finishing out some kitchen knives this am and noticed this pattern and curious as to what it is I'm seeing?

Blade HT'd AEB-L to 60rc by PHT
48" hollow grind

 
The spine is much thicker than the edge. The grinding will vibrate the blade but differently from spine to edge because of the thickness differenes.
 
I was hand sanding the blade and im curious about the very consistent figure 8 looking bands? Evenly spaced from ricasso to the tip.?
 
looks like some kind of magnetic effect, can you still see it after you wipe the blade off, perhaps there was grain structure realignment while it was forged at the foundry or during heat treatment because of magnetism
 
How did you shape the blade before hand sanding. The residual effects of grinding, machining, etc. can/will show up in hand sanding.
Things that are only a few thousandths high/low in grinding are invisible........but, will show up as ladder patterns and waves when hand sanded to finer grits.
 
Blade was ground on the 48" plenum from Nathon. I don't see it when I wipe it clean, and I don't have any problems, just wondering (out loud) what I was seeing.
 
R.Rock said:
Blade was ground on the 48" plenum from Nathon. I don't see it when I wipe it clean, and I don't have any problems, just wondering (out loud) what I was seeing.
Click to expand...

Please elaborate.
Are you saying the photo was after sanding, and when you wiped it off it went away?
Also, do you mean 48" platen from Nathan? A plenum is an air duct.
 
Wow I wrote the last post too fast, glad you knew what I meant not what I wrote.

Yes a 48" platen.

I was in the middle of hand sanding when this pattern appeared, it's only visible during sanding (600 grit in pic). You wipe off the fine dust and I can't see it.

If it's a magnetic pattern why this pattern?
 
somehow during the process the soul of that steel tried to talk itself into the handle. Your hand sanding must have provided the necessary vibrations, but id say that is definitely a form of communication between blade and handle(r). just guessing though.
 
Is your platen clean? What about the back of your belt? I have had gunk build up on the platen and not been aware of it and ended up with shallow patterns in my blade when using Jflex belts, however they are usually parallel to the spine because they are ground as I move the blade from side to side. That is the only thing I can think of, but it is hard to tell from the photo. Either that or perhaps if you grind towards the edge of the platen, your belts dig a little when the joint passes? I am just guessing here.
 
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