Grind mark removal

i recently received a nikiri from a custom manufacturer that shows significant grind marks. The marks are perpendicular to the blade and spaced apart. These can be felt by dragging a fingernail across them. The rest of the blade you can see very fine marks, but not feel anything. In my opinion these are from the initial shaping at a low grit. (Guessing still in the 120 range)

It looks like when he moved to higher grits, these areas were simply missed, or somehow the scratches were deeper and didn't come out well.

I think it's fair to say that he and i are at an impass, and I simoly want to remove these myself and move on.

I want to keep an even finish, and am not concerned with a mirror polish or anything close.

I also do not want to grind down the makers mark, even though simply using fits caused some of the black to come out of the engraving.

Can someone recommend a method and combination of abrasives that will allow me (by hand) to get those deeper scratches out, and then bring the blade to a reasonable smooth satin finish?

Any detail would be appreciated including places to secure this. I do have access to automotive sand papers through my business, but we stop at 120 because we paint all our metal. I have a sheet of the trizact 3k and 5k but that's not close to pulling these out?

 

Can you post a picture? Without seeing it, I'm going to recommend starting at like 80 grit and sanding in the opposite direction of the scratches to get a nice long satin finish. Go progressively from 80 to about 600 and it will look awesome. That why I do so check out my pics if you want to see how it would turn out.

 

Jared, would you do this by hand, just holding the sheet, or would you use some sort of pliable block?

Also, you say against the grain of the other scratches, not random like a da.....so try and keep my scratches parallel to the blade?

 

Just as Jared said, except that I would work in the -- vertical -- direction of the grinding. Yes, you will have to start at the grit that caused the problem. Use tape or so to protect the edge area, and take care not to overgrind any part. It's a huge operation as you will have to work on the entire surface. One of the reasons I prefer carbons as their patina hides all scars and blemishes...

 

I use a sort of block to keep even pressure on the sand paper. I guess it depends on the look you are going for as to how you make the new scratches. I like a nice uniform hand rubbed finish myself.

I think we are all saying the same thing at to which direction to sand by the way. Long sanding strokes (by hand of course) starting at the heel and pulling to the tip of the knife.

 

Direction could be different depending on your preferences. Personally I prefer horizontal direction (heel to tip) that Jared suggested. I also think it's easier to achieve with hand tools.
Cork sanding block is dirt cheap and makes things easier. Just wrap it in sandpaper and start sanding

 

Not so sure, I regret. If the original grinding was -- as I expect -- vertical, from to spine to edge, and that grinding is causing your trouble, you better follow its pattern.
Usually I use a coarse ScotchBrite horizontally to deal with any scratches with soft stainless clad but that is at another level of refinement and I guess you're looking for a finer solution.

 

Photos would be nice to get an idea about how bad those scratches are

 

I too prefer horizontally sanding. But if one, like the OP, insists on removing vertical grinding marks vertical sanding is the only option I'm afraid.

 

I don't think vertical sanding is the only way simply because all my knives start out with vertical grinding, then I sand horizontally. It's definitely doable, it may just take a lot of elbow grease and time

 

Any orientation is fine as long as you make the scratches deep enough.

 

I appreciate all the feedback. I am going to locate a cork sanding block and have at it. In reality one side of the blade is much worse than the other. And really only about half of that side is in poor form.

It's just very frustrating to me considering the price I paid for this custom, and the fact that I have maker knives at half this price with no grind marks at all.

 

That is a bummer. Cutting is obviously the most important thing when it comes to a knife, but fit and finish are a close second for me.

 

I actually bought a pneumatic 3 " da that has a soft pad hook and loop pad.....going to try that on an old knife to see how it works. Then if it's a good finish I will try it on the custom....anyway I have the 3 inch pads so I will hand sand them if the da doesn't work. Bought 180' 320, 500, 800....

 

Great issue presented by the OP! As a rookie, the better I get at addressing the cutting edge,
the more that fit and finish issues talk to me. In fact, I can not stop being bugged by the
scuff marks that come about by thinning. No matter, how well I think that I'm holding
the face above the stones, eventually, there's a mark here and there.

IF anyone does come across an efficient process, would love to see it posted with pictures.
It truly is a major undertaking to do a progression by hand, and to do so vertically can only
be regarded as a labour of love...should it actually be done!

I've come across two strategies. One is to back up w/d sand paper with gorilla tape...firms it up.
Another is of more interest--use slurry from either a slurry stone or from what can be collected
when flattening a stone. Could slurry be dumped on a hard stone and then move the face to impact
a vertical polishing? Or, apply the slurry to a rag which is then used as one would with sandpaper?

I will post a picture of a revived old Gerber carver. It had it's original (non ) bevel still on it. Thanks
to the generosity and curiosity of a member from another forum board, he put a beautiful edge on it.
Unfortunately, I eventually felt compelled to thin the edge in order to improve performance. Some of
the scoff marks are from past use and apparent loss of chrome plating(?), but I added my share.

 

there are many approaches that may work. Personally, I tend to flatten and refinish the entire bevel, and I usually like doing it in the same general direction as sharpening, if possible. Unfortunately, if you have an uneven bevel, stones generally don't make life any easier except some particularly soft, dishy stones, and even that is only for slight dips and wobbles.

If the bevel is wavy/wobbly and you don't intend to flatten it, the easiest method other than a belt grinder is to use narrower (2-3cm) pieces of wet/dry paper on a cloth or similar backing with a little give to it...not super soft, but soft. Control pressure to prevent the edge from digging into the paper when sanding. If there are pretty noticeable scratches, then start pretty low (~100 grit) and go up to about 400, making sure you remove previous scratches. At that point, switching to 3m sanding sponges (fine, superfine, ultrafine, microfine) while being careful not to round over the edge, heel, or tip, works well. I usually use those sanding pads after 800-grit stone finishing, and they are pretty neat.

 

xoomg,
Excellent details. Thanks!!

ps..at KKF that's me too...(nakiri)
Might say that I have some troubled children in the knife rack.

 

I would remove the handle, and go at right angles to the scratches until they're gone. You will have a consistent set of scratches. Then go to a finer grit abrasive, and go at right angles to your scratches until they're gone. Repeat until you're satisfied with the finish. This process allows you to assure that each successive grit has done its job, because the deeper scratches in the opposite direction from the previous grit have disappeared .